not that much more expensive is carbon fiber laminate. that stuff i have found particularly useful. just for info, check out www.cstsales.com. there they have anything composite. but to get to the laminate, visit https://www.cstsales.com/Carbon/carbon-laminates.htm scroll down about half way to "0.021 thickness". there, for a 1 inch wide, 36 inch long (the wingspan on those things is supposed to be measured from wingtip to wingtip with the fuselage attatched so you will pretty much cover the whole length) you can stiffen your whole wing more than all the other suggestions combined, while adding less weight than most of them as well. i have used this width and thickness both and they are really incredible. for your purpose, i would get that and put it on the BOTTOM of the wing, because if you manage to catch a wing or something, your wing will want to bend up, not down. use contact cement to attatch it because ca will eat your styrofoam away and epoxy is too britle to flex any. this will make your wing pretty indestructable while only adding about an ounce or two of weight while still allowing your wing to flex just a bit. i love this stuff. it is like a long strip of tape, and because it's fibers are unidirectional lengthwise, so if you line up the length with the leading edge of your wing, you will be very pleased i am sure. i discovered this stuff about a year ago, and i won't do wihtout it. i know at this point, it seems a bit extreme to go carbon fiber, but it's really not. it's just like any nifty tool.