I decided to post a separate thread on how well I fit the Harley Tallboy (52000252) Dealer Demo Seat. This is the one the parts personnel selected as being compatible for Tri Glide's and Touring Models with Tour-Pak and Passenger Grab Rails.
There are actually two model numbers of the Tallboy Seat. Model # 52099-09A for 2016 only shows compatible with Road King, Street Glide and Road Glide. Says it's not applicable to 14- later models with Tour-Pak and Grab Rails. Most unfortunate for me, because this model sets the rider back 2".
They installed Model # 52000252 early Saturday afternoon, and it also fit with my Mustang Backrest Mount and Backrest. So with backrest installed, I immediately set out on a 151 mile ride that included some interstate miles, but mostly state and rural back roads. This Model only gave me a 1.5" set back, which was definitely better than the stock seat. The rear of seat was quite firm, and after an hour in the saddle I began to feel a bit uncomfortable in the tailbone area. There was ample room to move side to side, but this would not alleviate the issue.
For Sunday's ride, I decided to remove the backrest to see what effect this might have. The same lack of comfort in tailbone region returned, just a bit later in the ride. Plus, I sorely missed the support of the backrest in the lumbar region. This day I did a total of 90 miles on the demo seat.
Monday, I decided to soldier on, so I put the backrest back on and went out to ride an additional 131 miles. Same results as previous days.
Tuesday afternoon I made the 42 mile ride back to the dealership to return the demo seat. All totaled I put 400+ miles on this model Tallboy seat.
I so much wanted to like this seat completely, it looks great on the trike and it gave me 1.5" set back. However, my narrow butt was just not a good match to this model's firmness in the rear of the seat. I'm pretty certain that after the miles I put on it and those from previous demo rides before me, if it were going to show signs of breaking in, it would have revealed itself.
On the plus side, I found out my dealership is also an authorized Mustang Seat Dealer. I asked about Tri Glide Demo Seats for Harley's Hammock and Mustang's Vintage Super Touring Seat's. They said they have them but they were out. Had my name placed on the list to be called when they're available.
So basically my search continues for a seat that moves me back and is very comfortable for my particular a$$.