Dave,
Did you take a look at the Adobe PDF file Tower has on the Uproar's assembly manual? It might give you a better idea of what goes into the assembly process. Wing area is 573 inches. Looks like a Tower 40 would be a fine match, if its running good for you. Unless you want a rocket. I've ordered a Fun 51 , and I'm also trying to decide what motor I want to use, either a TT GP-42 or a TT Pro-46. Guess it depends on just how much power you want on hand. I'm thinking a plain bearing 40 will still be a whole lot of fun. Then there's the problem of when the plane is "cashed", what are you going to want in the next plane. If its a smaller plane again like the Uproar, no problem. Just one interesting note, I learned to fly and flew a Sig Kadet Senior using a TT GP-42. Wing area 1150". Had lots of fun, going slow. I think a regular 40 in these planes is what they were designed for, why not use them. Tom