I have a Pizzaz with an Irvine .53 on it. It weighs 5 pounds, 6 ounces and needs all the thrust you can get. I'm running an APC 12.25x3.75 and a Tower muffler. It's a good combo. I haven't tached it yet, but it is clearly much stronger than my 46FX on the same prop/muffler/fuel. It will hover on this combo, but more power would make it easier.

If I had it to do over, I'd go with a Saito 72 or YS 63, or a light 2-stroke 60. I think the Saito 100 is a bit overkill.

Chuck