IMO any good .40-.46 engine will be good, as you can make an easy swap into another plane later down the road.
But as Big ED said, you will have to get the balance right. you will also have to learn throttle control, and proper prop selection
will be critical.

I use an older .40 tower engine on my PT 40 trainer and it has impressive performance. but with the control throws set to
low and an 11x6 prop It flies very tame provided I use throttle control. My flying weight is 5 1/2 pounds. and the wingspan is 60"
and it floats very good but not excessively like the kadet senior I learned on.