Russell Day long seat
I ride a 2005 Vn1500 Classic FI and couldn't stand riding for more than 50-75 miles. I'm 6'2" and weigh 245lbs with no butt, I sit on my tailbone.
I had a seat maker make some adjustments and it was better than the OEM but still not good enough for long rides.
I finally decided to pay the big bucks for the Russell Day Long and wish I'd done it sooner. First day we took a 250 mile ride (with several stops) and my wife and I were both extremely happy, and they say it gets better once it's worn in.
The only thing I noticed is the side wing part pushes against my thigh when I put my leg down at a stop and this pushes me forward slightly. So I readjust once I get going again, but it's not bad and worth it.
As a side note, we rented the Victory Cross Country tour which I'd heard had an excellent seat. After approx 250 miles (with several stops) I was fine but my wife said the rear seat was considerably worst than the Russell Day Long. She said if we buy the Victory she wants the Russell seat on it.