My callouses aren't obvious anymore either. In fact, the more callous is built-up, the more it hurts after a gig. If I'm going to sweat a bunch, that's when I use the fingerease, since sweat flushes away the oils. I do still have feeling in my fingertips, though probably not nearly as much as I should, I'm guessing..
I think the real issue George has is directly related to new stainless steel roundwound bass strings. They are often significantly less-smooth than other roundwounds, and not unlike a cheese grater until they've been gigged with and have some oil/dirt contamination on 'em..
John