Barry--
Dyno's are good tools to have... but the best test for a motor is ALWAYS on the track.
What good is a dyno result number if it doesn't help yeild good lap times or the motor only runs that way for 30 seconds on the track?
I would use the dyno to see what sort of things do what as far as pulling current, what produces rpm...all so you can try them out on the track and see what actually works best for you out on the track.
Then, once you have a good basline motor setup you can use the dyno to track the motor's performance over time or to compare differnet motors with simlilar setups to find your "best" motor.
Speedbug--
This might sound a bit simplistic...but just make sure your tires are glued well... we run 7-turn speed motors all the time and keep the tires on the rims....
Some steps you can take: clean the inside bead of the tire and the rim with motor spray or rubbing alcohol. Next, use a high quality CA glue... Losi blue or red generally get the trick done