20sf leaning post size?

[copout]

In the future I will be changing the seats out for a leaning post & was curious from those of you who have already done the change. What size/style did you go with & what changes would you make in hindsight? There are so many out there new & used, so I'd like to have a ball park size to be looking for in case one comes up that I can't let pass. Also any ideas as to what the original seats would be worth?