A buddy of mine and I have Nexstars and he has pretty much totaled his so he transfered all his gear into a cheaper Tower Trainer ARF. Well I have all his old airframe. The Fuse is totaled but the firewall is intact. I will use it to see how feasible it will or will not be to install an OS .60 FP that I have before reworking my Nexstar. I would think, but may be wrong, that the addition of floats would push your CG aft so the larger engine may not hurt your CG as bad as you think. Just to make clear I am no expert. So let's work together and see if we can find the easiest way to do this.