Free: Contests & Raffles.
a boonie cap would probably be 400 inches(4*12*pi + 10*10*pi [the top plus the rim is one big circle])a baseball cap, probably not4*pi*6*6*.5+rim(the sphere surface area equation is 4*pi*radius ^2)add a piece of cloth to the back (like those caps with the sun shade piece of cloth on the back), and you might hit 400.(get some blaze orange fabric from a fabric store and sew it on)Although, is it 400 sq inches visible from any one point, or cumulative?though I'm still all for vests, smoke signals, flashers, flags and everything else, almost got nailed last year, and my hunting buddies dad got a nice welt from someone not seeing him beyond a pheasant.