I am a bigger guy and I did my seat with the same methods outlined above with good results. However, I do question the use of memory foam, to me it would be too soft and not offer good support. I added 3/4" of "encapsulated" foam the bottom of the stock foam to keep my tailbone from bottoming out on the plastic pan. Encapsulated foam is the same type of foam used in those vinyl coated life jackets used for waterskiing. I was able to purchase it at a local upholstry/foam supplier. It worked great.

 

This may be my oppurtunity to do one of those cool instructional posts with directions and pics...

Thanks for all the advice.

Any other tips or words of advice are welcome.

Thanks again-

 

What about leaving the stiff stock foam on there, cutting it down slightly more than you want, cutting in a gel pan for the tailbones to equal it's height, then adding the softer memory foam on top of it all and shaping it?

That's my plan at present, anyway. I got the gel pad at Wallyworld for $21 in the Otto section. It's been good for runs, covered with nylon mesh bag material, but gets VERY hot in the sun, and when you ride, so it needs to be inside the seat. This seems to be basically what I can make out that the rebuilders are doing.