Hi halo fan, sorry for being offline for so long. Life got a tad busy over here
I recently made a foam torso section for my mk 7. I used the mk 7 template that is available in the armoury and scaled it in armorsmith (Armorsmith is a program made for cosplayers to digitlly scale 3d files so you can make them proportionally correct.) I'm 5'11" and is turns out 100% scaling works just fine for me. Are you using templates to make you armour? If so, are you having trouble figuring out how big to print them?