Saito 100 will be fine!! Nice engine i have one on my 7.5# giles and it flies it real well I would think in the Ucan do 46 it would be awesome. My brother has the Ucan do .60 and he has a YS 91 in it and it definatly doesnt have enough power for it. Hes going to swap it out with a 1.10. Try to get a small pitch and large diameter prop. Maybe a 16X4 I have a 15x6 on mine but its not a 3D plane. On my morris knife I run a 13x4W. I dont think the weight difference in the .82 saito to the 100 saito will be significant enough to have an effect on the way it flies but the power increase will be awesome. Some guys fly the 60 size u can with a saito 100 personnally I cant see how. at 7.5# it just does a good job IMO. funny thing is they recomend the saito 100 for the 90 size funtana @ 10#. I can see how that plane even gets off the ground.