Unfortunately most game characters are not life like proportions. Master chief is supposed to be the result of massive genetic and tissue alteration. Thus once the length is right, you might have to either bulk yourself up using undersuits etc, or cut out some of the pep to shrink the depth or width of the armor piece. If you do decide to slice the piece and remove some, save those scrap pieces of cardstock. They work great to use as pieces to rejoin/reglue the sides together. Remember the piece needs to have room for your undersuit, padding, strapping system, and reinforcement (fiberglass etc). Not to mention any battery packs, wires etc for led's or fans to be installed. Skin tight in the pep stage is bad.