Looking through my reference books, it seems the cuts of both uniforms are identical for regular uniforms, only insignia are different. Or are the books wrong?

There were differences in cut of the official uniform but it wasn’t long before W-SS uniforms appeared in the Heer style and there were also whole W-SS units equipped with the army design, so you’d not be unreasonable to use a figure sculpted with an army uniform as W-SS.

Andrew Mollo’s series on SS uniforms is invaluable for the details.

You do need to check as it depends rather on period. You may experience difficulty obtaining Mollo's series, as it was published in the seventies. I would recommend the Osprey series which are easily obtainable, and they have preoduced a compliation called "Hitler's Armies" recently. There is also a Waffen SS title called "Hitler's Elite".
The major differences were pre and early war, when the Waffen SS was still relatively small, and could meet its own needs via the Concentration camps (most contained a sweatshop producing clothing).
The first Waffen SS field clothing was in a unique Earth Brown, and the pockets in the skirts were slash ones at an angle, not box pleated ones. This design was intended to be worn with an open neck and collar and tie unlike the Wehrmacht issue, which could be worn open at the neck in warm weather but was not intended to be worn displaying the shirt. A subsequent pre-war issue in Field Grey retained this design, but shortages from 1940 on led to Wehrmacht uniform going on general issue to the Waffen SS also. From then on the Field Grey service dress was pretty indistinguishable and generally followed the streamlining and simplifications of the M43 and M44 tunics.
There are minor differences between SS and Heer Panzer Dress, The SS version has slightly smaller and more rounded lapels, without the pink piping, a straight rather than slanting cut to the front opening and lacks the prominent central rear seam. All or some of these differences may or may not appear on genuine SS clothing. Whether this is an issue to you depends on scale. Of course, the SS also received Heer clothing.
The major difference of course is in the widespread issue and use of various kinds of Camoflauged clothing amongst the SS, which is one reason why their units are so popular (not necessarily with figure painters!). It is impossible to go into all the variations here. Hope this is of some help.

Cheap (free) source of reference:
https://www.google.ca/search?hl=en&tbm=isch&source=hp&biw=1600&bih=769&ei=lB8gWvOzJoiI_Qa6mYnYDw&q=ss+uniform&oq=ss+&gs_l=img.1.2.0l10.5518.6070.0.11614.3.3.0.0.0.0.115.328.1j2.3.0....0...1ac.1.64.img..0.3.326....0.CI21HUuXd5k

A little note: black Allgemeine-SS uniforms actually became unpopular later in the war among the German people because they were worn by bureaucrats, and it indicated that the wearers were draft-dodgers who were safe at home rather than at the front doing the fighting.

So did the Wehrmacht use camo uniforms? I have Dragon's Sturmpioniers 1942 Eastern Front and it shows them in camo uniforms similar to the Waffen SS; same with MasterBox's German Infantry Western Europe 1944-45; neither set identifies as representing SS units; please forgive my ignorance (and/or failure to research more) but what is going on there?

The figures in the sets you are referring to wear the so-called splinter pattern uniforms such as zeltbahn:
https://www.google.com.ua/search?q=wehrmacht+zeltbahn&client=tablet-android-lenovo&prmd=ivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwio94ydoefXAhVSZlAKHYovB10Q_AUIESgB&biw=1024&bih=600
WSS had two types of oak leaf pattern, pea pattern and (borrowed from Italian army) splinter pattern, as well as some more esoteric variations:
https://www.google.com.ua/search?client=tablet-android-lenovo&biw=1024&bih=600&tbm=isch&sa=1&ei=aXogWqTaIYvfwAKYzIbIDg&q=ss+camouflages&oq=ss+camouflages&gs_l=mobile-gws-img.3..0i13k1j0i13i30k1l2j0i13i5i30k1l2.319013.327608.0.328579.15.11.0.1.1.0.1218.6662.2-1j3j0j3j3j1.11.0....0...1c.1j4.64.mobile-gws-img..3.12.6743.3..0j41j0i67k1j0i30k1j0i5i30k1.0.SMTKNNTH_l0
There were some substational differences in design and detail, as well as the amount and commonality of use of camouflaged uniforms between Heer and WSS units throughout the war.
https://78.media.tumblr.com/e7fde94705598441d443c3afebd27d6d/tumblr_oozsf52kMK1r94kvzo2_1280.png

Thank you; I thought that was probably the case as the patterns were different; follow-up question (again please forgive my ignorance): was the mix of camo tunics with solid color pants (and the reverse as well) personal preference or a matter of what was available from supply sources?

They used what was available in all possible combinations as there were no strict regulations as to what can and what can't be worn. There were a lot of custom-tailored unique designs too.

Thanks; that's what I figured;

Heer also had a pull-over camo smock. Main differences between it and SS was it had an attached hood and lacked elasticated cuffs, and it only came in splinter pattern camo. This is a re-enactor copy, but is similar to originals:
http://www.godarsinc.com/WWIIGermanTunics/CamoSmocks/tw44smk1.jpg

Appears to be made of same material as Fallschimjager jump smocks.

I read somewhere the Hugo Boss designed the early SS and dress uniforms.

No ,he produced the uniforms for SS,SA,HJ,WH and others goverment stuff like post,rails,police etc... but he did not draw them

Two employees of Hugo Boss were members of the SS, Karl Diebitsch was an artist and Walter Heck was a graphic designer. Although Boss was a Nazi Party member and supporter of the SS, they did the design work.

G

He was definitely a Nazi even before Hitler came to power, he even used prisoners in his factory,was anything but a saint,had not joined the party just for businnes like others, he was a fervent national-socialist, simply he did not directly put his sign on the uniform drawings but did all the rest

Funny how many of those pictures are of sets for 1/6 scale figures. (And the 1/6 female version as in Ilsa: she-wolf of the SS

The black Allgemein SS uniforms were officially limited in use "for the duration" and replaced with field grey around 1942. But Hollywood never got the memo so most think Gestopo in 1944 were still strutting around in them.
"Klink, vhat IS THIS MAN DO-INK HERE!!"

Sorry whenever I see lots of pictures of the black SS uniform I think of Col. Hofstetter from Hogans Heroes or the movie To be or Not to Be when Jack Benny wore one.

Yeah, unfortunately a lot of those pics are of action figures, but there are still quite a few links to original photos, museum pieces, and good quality replicas. And it's a good starting point right at your finger-tips.

Ahem, unfortunately? Some of us have those figure uniform sets. I have a few web comic scripts requiring them and at least one Nazis has to have a black SS uniform in any story. It's a trope.

And a lot of my work is all about twisting cliches.

It is my understanding that the black SS uniforms were phased out after the war started except for dress and official functions like the LAH guard units. The bulk of the black uniforms were stripped of insignia and reissued to foreign police [ Schuma ] volunteer auxilliary units in the occupied territories in the east. This is why so few original black SS uniforms survived the war.