Re: Replacement reel seat
it might be easier to address the reel's foot than replace the seat. some file the ends a bit. which reel is it? on a machined reel, you can sometimes buy a replacement foot if it's from a major manufacturer like orvis, lamson, ross, etc and file one down, retaining the original in case you mess up or want to sell it as original someday. how much is the fit off? if it's a machined reel/footing, you could always have someone manufacture a replacement foot and i know of one guy who specializes in this work. bill archuleta.
i have an okuma integrity (blech) which had a slightly large foot. i resigned myself to use it on the one rod which it fit. these days i don't use that reel at all.
to replace the rod's reel seat, you'd have to first find a replacement reel seat which fits and as you've experienced, there are no guarantees. if you mess with the rod, you might invalidate the warrant if it has one.
if you pursue removing the original reel seat, it might be easy to remove but you might screw up a portion of the rod. might. once removed, it's generally easy to glue on a new one if you take your time and do to right. but chances are it would look tampered with.
what makes this your favorite reel and what is it? since you can never have enough fly rods, it might be worthwhile to simply find a new rod and insure the reel fits well.