Rob,
I have a 1/2 A stealth w/ a Norvel .061 Big Mig RC. I got the plane in a trade or auction or some thing and it included a reed Cox .049. I flew it w/ that a couple of times, but the Norvel is far more fun. It flys great- very easy to control and I fly it like a crop duster - very close to the ground just over the top of the weeds at full throttle and w/ full confidence. It does loops and rolls, stall turns etc. Great fun and a can't lose plane.
If you use the Norvel tank mount it will fit right where the Cox w/ tank was mounted before- otherwise you will need to modify the engine mounting area to pull the Norvel forward for balance and the prop to clear the cheeks.
Go for it, Dale