Your floor sounds interesting. I am sure it will turn out OK. You might want to think about whether or not you really want to put a heavy-duty finish on it. If it is indoors and in a location where wet shoes are not a problem, I have seen a nice almost natural sanded floor finished with what appears to be a deck waterproofing compound. Check out these folks and ask them what they do when they install their "old" floors (email@example.com). Also, see their website and note the French country-style ambiance they bring to the place. http://www.lamadeliene.com Those folks are a popular chain of restaurants in Texas area and have coffee spills galore on their floor. It always looks good, and must be very durable. Check them out to see what they do to their floors. Good luck ... you might be able to just sand the floor and apply a good waterproofing substance to it ... kind of like and "indoor" deck.