So it occurred to me recently that there's not exactly a shortage of knowledgeable techies within "these types" of music whom offer mastering services; like Viktor Ottosson, Pekka PT, Pentti Dassum, Sean McCann, Jason Lescalleet, and probably others I'm forgetting. I'm considering having an upcoming piece "mastered" as I don't think my limitations can do it justice, but with a little tweaking beyond my capabilities, could reach it's potential.
My main question is this: do these types of guys offer by-commission services at specific rates? Or is it a more "Steve Albini" type of thing, where their available time and interest in the project is a determining factor in whether they'll master your stuff?
Anyone have experiences with any of the above-mentioned? Any advice to offer? What can a novice expect to spend to have a full-length release mastered?