Gday James
No worries on the asistance, but bear in mind I may be a pest now...
Looks as though you are really forging on here!
The effort is showing, although there are a couple of things to touch on...
Your 'vane' sight looks as though it is one solid piece? If you still have the kit vane, have a look at how there is a horizontal join at the midway point, where the top half is attached to the inside of the lower...It also should sit square when viewed side-on...
Also the hatch handles are maybe a smidgeon too large... It may be that they seem to protrude a little too much?
What have you added to the split hatch without the periscope? I can't remeber the last time I built a wet versioned Sherman, but I'm pretty sure the split hatch is the same as used on the mid production versions, and IIRC there was sometimes a square pad, but it may be slightly smaller than your addition.
Also, don't forget the periscope to be added in the front right protective housing on the turret!
There also need to be drain holes drilled into the splash guards around the fuel filler caps, air vents, etc. Easy to position, as flush with the hull surface, and central to the semicircles around the fuel caps; basically where it would drain the liquids that would pool there (gasoline, rainwater etc)
Gimme a hoy if you need further placement info and anything else I can pester you with
Cheers
Brad

You've confused me slightly though, Should I put in two 90 degree bends like the PE one or cut it in two and glue one side against the other?

The cowling should be much thinner than shown. You can also make a small cap (like a puck) which was placed on a small knob next to the spotlight base, and joined by a small chain to the light mount.