Hi Rob,
I'm 6', so not as tall as you. I took both for a test ride, and I would encourage you to do the same. I hadn't even considered a scooter until a friend bought one which he showed me........he swears by the Sport, he test rode both and that was his choice. If you read internet reviews and watch YouTube clips, the Sport gets the edge. It's lighter, so nippier in traffic and easier to throw into corners than the GT. I was convinced I was going to buy a Sport so took one for a ride. Came back to the dealer and took a GT for a ride. My immediate impression was WOW! I didn't find the Sport at all comfortable, but the seating and feet position on the GT is comfort personified. On the GT, I feel like I'm floating along sitting on a armchair.
Bottom line, for me it's the GT, for others it's the Sport, so you really must try both.