Where in Portland are you? I would suggest someplace like the Community Cycling center or City Bikes that has tons of used seats available for CHEAP. You can try some different ones to see what works for you. Just don't get one that is so old that the foam is trashed.

Performance will also let you buy several seats with the intention to return the ones that don't work for you. I would feel guilty about this if their sales people weren't the ones who suggested it in the first place.

There are also shops that have test seats (colored differently) that will let you use a seat for a week and then keep trying seats until you find one that works. I think Sellwood Cycle does this, and Lakeside Cycles in Lake Oswego, and I'm sure there are others that do, too. Ask around.