Steve,
I wouldn't particularly care how many holes there were, as long as they were good holes. Of course, this is assuming that the pace of play would be reasonable.
I really doubt that 80% of rounds at Sebonack will go 19 holes. One because it isn't customary, and two because 19 criss-crosses #1. I know the course won't be inundated with golfers, but I just don't see that % happening. I would imagine #19 would end up being a place to work on your short game.