Hello; Norm has a good idea with the ply ribs. I cut aircraft ply (5-ply) ribs for the second Ultimate I built. The original ply ribs were the first thing to crack, and it's quite hard to replace a rib in a built wing. I used two wing servos too, in the bottom wing. I put a Saito 120 in it at first, but after flying it for a season, I went to a Saito 91. I think I prefer the 91 since it makes the entire plane lighter and more responsive. There is another Ultimate at our field, he put a Saito 91 it that too after watching me fly mine. The second ultimate I built had been soaked in a garage flood, and I had to replace most of the wood. I didn't think it would work out, but it came out one pound lighter then my first one.