I got the height for Garrett Jones off his own MySpace page..
and it is confirmed by the listing in IHSA which obviously come to IHSA from his own school, Evanston High School.
http://www.ihsa.org/activity/bkb/2007-08/4info1.htm
I don't know when he updated his page, and I suspect he was 5-8 at that time...and the IHSA listing is from last year, but at least I have cited some credible references...
and we all know kids and their coaches, AAU coaches, and schools can tend to exaggerate heights...so who knows, really...
If you say he's 6-0, then it's possible, he may have grown...but most sites list him shorter,
Here's one local prep site that's generally pretty accurate, that has Jones listed at 5-10..
http://blogs.suntimes.com/hoopsreport/2009/05/the_next_25_in_2011.html