I was able to remove the screws with a small square head bit. I will have to check again what the pattern actually is. They were a complete PITA to remove while worrying the whole time that I was going to strip one. Why they are torqued in so much I don't understand. I ran some thread lock in (light duty) so they can be removed with a little force but not back out while bumping down the road.
'12 Sunseeker 3170