If you have it so it feels comfortable, stop trying to make it look pretty. It will smooth out somewhat with use and you will forget about the little dings.

-Wes

Just have to agree here, in as much as making it look great and presentable seems to be the part most people are trying to emulate and do, it is not actually how it should be done.  What you rather have to aim for is making it feel comfortable when you are riding. And in that case, you just smoothen it out on all sides.  Not worth it to have one that looks rather great than comfortable on the rider.

I made hip & knee braces of miniceel, and had the same problem.  I finished off the edges that wouldn't get smooth with a very small flame on a propane torch. Use a very small flame, and carefully approach the foam. When it gets hot enough, the rough surfaces will start to look "dark", as the cells close.

I tried that Jim 777 with the flame. Great idea and it does smooth it out as long as your careful not to over due it.

thanks

I also carved a new foam seat for my hybrid WD.  Didn't like the way it looked( or felt0  so I covered tops and sides with black nylon (wrapping around to bottom edge),

Used a special fabric glue. It has held up well, is comfortable, dries quickly, and now matches the stock black nylon covered seat back.