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The Anniversario seat has a convex shape on top, it is possible flattening that shape might be enough to increase your comfort, or possibly add softer (or firmer) foam.
Note what Rob said regarding the shape of the seat-- you'd be amazed at the difference once you've removed all the dome and created a very slight dish in the otherwise flat seat. A belt sander will do the trick in no time, and the seat cover can be stapled right back in place.