I made my 501st approved Stormtrooper costume back in 2015. I was going to Star Wars Celebration in Orlando and 10 days before leaving, decided to build out a Lego Stormtrooper cosplay. It was a lot of fun and long hours and it was well received at SWCO. I used foamboard from the dollar store to create the legs and torso. EVA foam for the hands. The front and back are printouts glued to the foamboard. The helmet is from my regular Stormtrooper cosplay. Pics below from SWCO and some measurements if you want to give it a try.