I'll go on this one. I coach middle school wrestling at Doe Creek Middle school, and have for the last several years. I'd say we're a very good MS team (MS State- 1st 2009, 2nd 2012). (Not the top in the state, but top ten or better for sure) Anyways, I show most moves I know to my middle school boys, full aware that I have a variety of different body types that will be able to do some moves and not be able to do others. I will even tell the boys, for example, "most big guys this probably isn't for you." I don't have the luxury of a huge coaching staff (2 of us for 40-60 boys), so some kids are learning moves that I know they'll never use. I have no problem with this, and here's the reason why........
What's to say that tomorrow that they don't have a match against a kid who uses this move as their bread and butter. Practicing a move, learning the intricacies of a move, etc. will my wrestler defend that move. I think it's important that the kid has a full knowledge base on the moves. Also, what if he grows a great deal, or gets skinnier, or gains weight, and his wrestling offensive therefore changes?! I understand you would want someone to fully train him for moves specific to him. If he was older, I would grasp that even more. At his current age level, I would say that he needs to be a sponge and learn as many moves as he can. It's not a bad thing!