re Neetsfoot oil....I weigh 140lbs and my B17 took only maybe 7 hours of riding to stop making my sitbones sore (it improved more over time after that) so its unfortunate (and hard to see why to be honest) to read of your discomfort.
Did you put proofide on it? Given that the imperial has the cutouts and because of this has more flexing-- compared to my brand new b17 (and me at 140) it strange it doesnt work for you. My guess is seat position (but could be other factors as well, what do I know, your body shape, your clothing, I dunno.)

sorry, re the oil, just be aware that oils soften the leather, and if you soften the entire thing, it will sag, and wont be supporting you properly , ie the indents only where you sitbones are. If the whole thing becomes too soft, it will just sag like a hammock. If you over soften the leather, you cant go back, so just be wary about what you do (or extremes anyway)

you pays you money, you takes you chances. good luck, and if it doesnt work out, just sell it (be aware that over softening it will pretty much take its resale value away--I bought a used B17 with barely any bolt tightening, and it now fits me well (the guy who owned it was slim like myself, which boded well-it took about the same time to break in as my new one, a bit more as the leather is stiffer than the newer one)

good luck