Ken:

The performance on two .61s is better than a single with a 1.20. The twin is heavier than the single, so even though it is faster, it doesn't have quite the vertical that the single has. Still it will do BIG loops. I wouldn't want any more power and adding weight that close to the CG wouldn't help the balance much.

But the 65AX might give it a little extra pull and the 75AX is only 3 ounces heavier.

PM coming.

Jim