For the little guys, the smaller & lighter the better. HL makes a motive in 109 & 119 for riders up to 105 on the 109 and 115lbs on the 119. Both boards will be more than enough to pop him right up, but will allow him to control it better so he can progress. My 7yr old is small and light and rides the 119, but Santa might bring a 109 so he can progress even more.
This board is even better for the older guys, we have a 12yr old that has a 131, that will ride my sonís board when he is with us, and I also have a mom thatís over 120lbs that rides it also.