I thought you had already bought it! Well either way, congratulations! You did get the 12.17, yes?
Crawling is about the most reliable way I have found to find a good spot for a subwoofer. There really isn't a whole lot else you can do aside from just moving the sub, then listen at your seat, then move the sub again, go back to your seat... essentially it's the same idea as crawling around the room with your sub in your seat.