Breaking in the saddle is not the same as breaking in a baseball glove or a pair of boat shoes, you don't want it soft and flexible, you just want its shape to adjust w/o any of its physical properties changing. A teeny bit of mink oil might not over-soften it, but then it might also not get you where you want to go anyway. Time is the best, and it doesn't even take a lot, just a few hundred miles generally.