Congrats on the bike. I bought mine last June. Overall, I like the bike pretty well. I've been slow to change a couple of things I didn't like, but I'm just about to correct the last one so I think I'll start digging it more now. The windshield was too short for me and the bars were kind of a reach (that extra inch I have to stretch makes a difference). I just replaced the stock windshield with the Roadster ($210, blade only) and have the Rivco risers ($180) on order. They'll bring the bars back 2 inches. That's all I need.
As far as seats, Triumph has two other two-up seats for the R3T, the Long Haul and a gel seat. I bought the Long Haul solo seat (wife doesn't ride that often) and it's plenty comfortable. Then again, the stock seat is fine too as far as I'm concerned, I just wanted a rider backrest and the look of a solo seat. Plus, I weigh 150 if you soak me down good with water so pretty much any seat has enough padding for my rear end.