I see you've ordered a Corbin seat.I have the Corbin on my America and I strongly recommend it.I can use the backrest or for short hops leave the backrest off.I have tail bone/back problems too and it allows me to keep doing what I love which is riding.
If you happen to find out what brand the peashooter mufflers are let us know will you? They could be stock Triumph with modified pipes.
I really do like the look.