Seth, before you spend the money on a new seat, try some cushions first. You can position the cushion forward so you're only sitting on the rear and compressing that enough to get the rearward lean.
Those cushions that use adjustable air bladders, such as Air Hawk, will probably work best for that. Of course, they are also the most expensive.
You'll spend no more than half the cost of a replacement seat, probably less. If it doesn't work, hang on to it. Even the replacement may some day need a cushion.
2003 GL1800/MotorTrike Adventure IDMWT#25x3
Ride often. Ride far. Ride safe and do much more of both.
Give a man a fish and feed him for a day. Teach him how to surf the GWOF and he won't bother you for weeks, maybe months
I'll be waitin' for you at the end of the road.
If everything had gone as planned, it would not have been an adventure.