70" here I'd be using the 91. Had the 80" Great Planes 27% Cap 232 with the OS 160 that it called for, and it was barely enough.

The Husky actually balanced perfect with the 120, and here at 4600 feet altitude it works wonders having a little bigger motor. Not to mention prop size changes. Can't run the 14X7 3 blade on the 120, have to run the 15X7 for the same RPMs as I would get with a 14X7 at sea level. Now having the floats on the Husky, a 120 on the front is even better. I'm sure near sea level a 91 would work great. I went ahead and sprung for the more costly Sea Commander floats, and they have been well worth it.

Before you get to building yours, if you are thinking floats down the road, go ahead and build yourself a nice hardwood block the bulkhead behind the one the servo tray connects to. Saves a lot of hassles. I've seen more and flown a few on floats and I am more than impressed with the Husky. Have the step right on the CG and it takes a tiny touch of the elevator to get her off the water after shes up on step. Landings are unbeatable hands down. The second pic is how it comes down the entire glide slope.