I'm currently riding my 6'6" as my 6'4" is getting put back together, snapped it surfing. It's too big but still usable, my 6'4" feels better.
I have tried using an older 6'2" but it just flexed beneath my feet too much as it was quite thin(2 1/4" thick). I just kept waiting for it to snap. Still think around 6'2" is ideal.
Before you put in the footstraps just try out your old one and see how it goes.It's really good for your kiting to go without footstraps. Just give yourself a little more space than normal from other people as you come off a bit at first jibing and riding toeside.
Havn't tried a you beaut shop one yet but am eager to try...
Just got no $$$$$