Thanks for the kind words guys - and also to Barry C. for his advice and encouragement. I've now ventured outside and run up the motor. Full throttle current draw is around 45amps giving about 500 watts. This works out at around 70w/lb which ought to be okay. It may have to wait until the Spring to find out though - at this time of year I tend to reach for the models that involve little or no slopeside assembly!
Yes, as a glider it's pretty well sorted so, as long as I've fitted the cg back in the same place and the thrustline isn't too far out, there shouldn't be any surprises on the re-maiden. But you've heard that before