I have sheeted my wings with 3/32 balsa on the bottom and 1/16 balsa on top. I have also used fiber glass cloth on top and bottom. Sheeting makes the best flying gremlin, however its too much work for a gremlin. The Bi-Di tape method is the best. I lost 5 gremlins in mid airs last year. The sheeted one's make the loudest bangs!!