Hi
I'm going to paint the HB SS-23 in the light green version.
Would anyone know wich colour to use? (Tamiya or Mr color ref please). The colors suggested by the instructions don't seem to match (XF 20 is a kind of grey and H303 a dark green).
Thanks!

Well, light green would not be the most accurate color. You should aim at getting as close to slightly faded tint of XB-518 as possible.

I would start with mixing 2 parts of XF-49 (khaki) + 1 part of XF-58 (olive green).

What line of paint? I prefer to use Testors Model Master Acrylic 4726 "Dark Green" as the base for my models. I use light tans to lighten it up for other shades over the base color. Works well enough for me:

Here are some pics of what I'm asked to do by collector.
I think I will try a mix of olive green, sky and khaki.

Are vehicles in service faded and rusted so much? This one looks esposed as a gate guardian or in open air museum, without maintenance.

Tamiya makes a really nice yellow-green that can be used for this faded color. Don't recall it off the top of my head thou.

It's XF-4....Yellow Green.

(as noted in another thread) The problem is the color you want is not a "standard" color. It is either a sun-bleached color, a incorrect museum refinish, a color imbalance in the photo....or a combination of all three. You will probably have to mix up a accurate color, but another close option (acrylic) at places like Walmart and such is Apple Barrel's 20472 Leaf Green.

To go along with what Jacques said, the color is possibly not a standard one. That is why it may be a good idea to explore the other areas of the paint rack.
By this I mean check out colors not necessarily intended for the given subject i.e. naval, aircraft, and sometimes even automotive colors. I got into the habit long ago of painting the caps of my paint bottles (I don't trust what colors the caps are molded in too much), and rarely look at the labels unless I need a new bottle. This allows me to look at a range of paints and quickly find one that "fits" as well as see which colors look right together. It also minimizes the problems caused by manufacturers' consistency issues.

(As an aside, I got into the cap-painting habit since PollyScale paints had a tendency to cure to a different color than how it appeared when still in the bottle.)

If you were willing to try Model Master paints, it appears that (to my eye) the color in the second photo matches my bottle of MM 2081 (RLM 71) fairly closely.

Interestingly, it looks like someone started to draw the outlines for a camo scheme and then quit before putting on the second color.

Thank you all!
After discussion with the commissionner, I will use the mix of khaki and olive green suggested by phil.
I will post some pic when it's done.

With a 50/50 mix of khaki and olive green :

Are you sure it's a 50/50 mix? On my display it looks more like 2/3 Khaki and 1/3 olive green...

yes it is, no doubt, on a light grey basecoat.

Yellow+Black+green.