agexpert...
You have to mount the engine inverted but that's not a problem on the 46. The 60 leaked a lot of fuel the 46 doesn't. Follow the directions and you'll be fine with the tank mount. The Saito 82 (not Saito 80) is a very good engine. It's what I have and it will 3D anything. Try to build it as light as you can. I'm at 5lbs 12ozs. Works very well. That's the biggest engine you can use with the stock mount. Utimately the 100 is a great choice also. But it's heavier and harder to balance and install. If you go 91, the Saito 82 is move powerful and lighter.
Thanks
Barry