I am 6'5" and have the T2+ tent. I fit great with gear inside. I would go with the REI tent for a few previously mentioned reasons. It is plenty big for you and your panniers, my T2 is less than 4lbs, it is free standing, and you cannot beat the service and warranty of REI.
I think carrying a T3 would just be extra weight, unless you enjoy having the extra room and don't mind the trade off of weight.