I've never heard a complaint about the comfort of the Russell. I have a Corbin and like it, but its my third Corbin, I like hard seats. Hard to know what suits you. The Russell will be custom made for you and you're more likely to get a good result.
As to which seat pan to use, are you going to get front and rear rebuilt, or just the front? That probably will be the deciding factor.
As to the look, well you can't see it when you're sitting on it. The rest of the time, well the Rocket won't win many beauty contests as is, so if it were me, I'd go for comfort over aesthetics. Besides, the R3T is one of the few bikes that can take the oversized look of the Russell in stride. It looks out of place on a lot of smaller bikes, not a problem with the R3T.