I agree somewhat with S Wallace on the fact that I don't believe that you want to use silkspan on the wings. You will forever be patching it. Silkspan is great for solid structures, but it punctures way toooooo easy. Darhma 5mm silk (if you want to do a traditional covering) would be a good route. You can forgo the silver on a trainer like was stated, but I would continue with the filler coat. Fills grain and weave faster than straight dope and sands easier. The filler coats would go after the 2 to 3 seal coats and when sanding a wing that has not been sheeted, use OOO Steelwool. Sandpaper will cut thru the covering at the ribs. You will need to run a strong magnet slowly over the covering after doing this. You will be suprised at the little pieces of metal you will pick up. Unless you truely are looking for that traditional look, I would just go with an iron on covering. Just my $.02 worth.

Good Luck,

John