Hey, where are you located, there are a few members that can help placed around Sydney, Canberra and Newcastle, so depending on your location we can help you out.
I did the paste thing and it didn’t work, I think it’s a hit or miss, I ended up painting my entire armour because there were different shades of yellowing. Surprisingly the paint job turned out pretty good. In saying that one of the forearms turned back to its original colour of bright white.
All great awesome pointers but remember measure twice and only slight trim, once it is cut off it’s very difficult to put it back on,
have a look at some of the build threads of past they may help.