Sunshine:
Cutting back the wheel boys shafts for kids is not going to let the kid have any chance to shoot acurately.Those broken shafts were already many times over the spine a kid needs , and cut back even further they will be like you shooting a 400# spine shaft.
You can make ramin shafts from 1/4" or 5/16 " very cheap, or buy some of the Alum / carbon shafts for kids without breaking the bank.
If we want kids to stay in the game we need to match up their arrows just like we do our own.
Pete