I've always been a COX fan.
Just keep in mind the original weighed between 10 and 12 ounces and it flew pretty good with just the Production .049 in it.
I would suggest using a Master Airscrew 7 x 3 prop for your first flight if you're going to run the Big Mig.
That will give you plenty of "pull power" but keep your lap time down to just below 4 sec on 42' lines...
Greg
Greg, Thanks. I'm actually using another approach for achieving a good speed for a Stunt run, which I think better suits the pressure bladder feed. Rather than heavily propping the engine, I'd rather use a short flat prop so the engine runs in its peak power band where it's able to turn max RPMs and get the benefit of its SPI and no bogging in hard turns. I'll tame the speed with a low pitch, like an APC 5x2, 5.25x2 or 5.5x2. With the APC props, even a 6x2 will still allow either engine to peak. There is no other brand besides APC that will do this at 6" length. I know there are lots of people that'll think my approach is crazy, but I it works on 1/2A performance engines. If I was running on suction, this may possibly be different.
I started a build thread in the Open forum.
Rusty