Yeah Waldo, I am also waiting for you to put the OS 61 on your t---t and give us a comparision test.
I think a 25 size T---T would be great. The most important thing is keeping that airfoil. does any one know the airfoil number. If I had still had my book on model airplane design I could firgure the number out. It's been some years but the # reflects the length to thickness and where that thickness is at on the airfoil.The blunter the leading edge is the more gentler the stall, and more induced drag, while the sharper the leading edge is the less induced drag, but more radical the stall. That is why the T---T hairrers so well is her thick leading edged with a really thick airfoil.