RE: 1/2A Honker
If It's at 24 oz I'd go with the 074 because your going to have to add a tank. If the dragonfly is flying the thing now the .061 will also be a big improvement.
.061 - APC 5.7X3 or cox 6 x 3, 1oz. tank or DB's film canister tank (very light)
.074 - APC 7x3 2oz. tank
Just my opinion
Rrragman