All the info I was about to say you seem to have already figured out! haha
Dyl Pickle asked about finding a foam unfold for chief's ab section a while back, perhaps your unfolds will be able to help him too! Here's where he asked the question:
Working on a chief mark VI suit currently and after searching for awhile I can't seem to find any sort of blueprints for chiefs core section. I'd preferably like to make it out of some thinner EVA. I've seen some people make the basic gen 3 undersuit but its a bit different then chiefs.
www.405th.com
I used 4mm EVA foam for my ab wrap. 5mm will do the job just fine as well. I tried to use a zipper to do it up but I found that if the seam that the zipper is not a straight line it can sometimes have trouble closing. I ended up just using Velcro to close the seam. To get it on, I put it on backwards to access the Velcro, and then I spin it around.