Jeff, sounds like your son is a "chip of the old block"... do you have that saying over there? Means he's like his old man, real tall and probably still growing!
Rockethead, there are no "pitfalls" with the Rivco risers except that they will do away with shoulder pain, neck cramp, wrist ache and probably fix yer bunions as well! :-D :-D
Seriously mate, they're the "dogs bollocks" to quote an ex-pat pommie mate of mine.
Davo