What Foam Thickness to use for Star Wars Clone Trooper Armour.

So I got the idea to make a custom costume using a variety of different armour pieces from all sorts of stories, such as Star Wars. I'll probably be using it some Films. But the problem is with Clone Trooper armour is that if the Foam is to thick, it will look really weird. I've seen many people do it before. So I was wondering if there is a thin foam (But still thick enough) to do the job right? I know on 501st they sell ABS kits of armour. It looks perfect but that can break easily. And I want the costume to have some strength and comfort to maybe.... I guess fall down for an example. Something around that area. Any help is appreciated. Thanks!

Try about 6 to 10mm these are the best in my opinion because if its less than 6 it will be to weak.

I use 6mm myself and have had no problems