My son is 4'7", so I'll probably look at the 65 and a gross of plugs.
I think you guys are correct: I would rather have him comfortable on the bike and not struggle on a too large bike (I already went thru that with the XR80-his first bike)
I also have a 13 y/o daughter (5'7" 125# XR100), so I expect a KX85 may also be in the near future.
Financial note: My wife is super-thrifty: I just discovered that she has been saving (yes, saving) all her paychecks for the last several years!!!!
So when I told her that we wanted to upgrade bikes; She said no problem!
What a sponsor!!
Mikey350D