Concerning the new bottom I didn't put anything on top, just four 1/2'' by 1'' pieces on each side of the plywood used to replace the bottom.

Unfortunately the weather is been a little hectic here (very windy + snow[:@]) so I'll need to make more flights before I can comment. From what I can remember I have the same observations: the plane is fun to fly, it won't slow down very easily but I think it's a matter of getting use to it and practice stalls at high altitude.