My youngest who is in the top half of the 8U this year went 43,49,52,58 and 64 this year.
My other son who is 1 year older and is in the bottom half of 10U this year went 49,49,49,52,58 and 67 this year.

The big jumps the last two year made me nervous about their ability to handle the strength differences. However, they have both bought into the concept of good overall fitness and that lots of pull ups and push ups year round are the best way to turn that extra mass into useable muscle.

As a former HS coach I am familiar with weight management but have found that with young kids you are generally better off focusing on superior technique and getting into great condition. The trade off of getting one weight lower usually is not worth the mental and emotional strain to kids younger than 13-14. It may cost you the occasional match against really tough competition against bigger kids but it reduces the rate of burnout. If a kid is really serious and has long range goals such as HS, college or beyond he will have plenty of years to manage his weight. They need to learn their technique and become students of the sport at this age.