GT / R Seat Comparison

As far as I'm aware the GT seat is the same shape but as it sits you lower, while you'll maybe have more arm reach to the bars you'll have less leg room to the pegs so your knees and hips will be more bent. That would be an issue for me and I'm only 6' tall. I have a GT and I also found the pillion pad intrusive at first but I seem to have got used to it now as I no longer notice it. But it does feel very sculpted with no wriggle room. You sit where it puts you.

I believe - though I haven't tried one - that the Corbin sits you higher than the stock GT seat and is longer so you have more room in every direction.
Before you pull the pin on a GT seat I'd get to a dealer who's got a GT in the showroom and ask if you can swap the seat over and just try it for size.