I would think it should fly pretty good on a b-power pack with a smaller battery. You'll have to experiment with the location of the battery pack due to the extra weight of the motor. The only one I motorized used the pod mount above the wing and the radio battery was 4 AAs under the hatch so I'm not sure what to tell you about balance but I'd finish as much as you can then experiment with the ESC/Battery/Receiver locations until you get the balance right. Thinking about the actual flying, I'd either set the timer or the telemetry to give an earlier notice than normal to leave plenty of power for the radio so you can glide for a long time after the motored portion of flight. The motor pod/glow version was always good for 5-10 minutes of flight on a normal day with parking lot thermals in the summer.