Jeff, I think the mast is going to need to go somewhat forward of the hatch, and therefore will disrupt the V berth. You might just be able to use Annie's solution for Fantail, and have the foot of the mast at the aft end of the V berth, with a forward rake. This will leave room to scramble into bed, but it's tight. Adding a conventional tabernacle will make things tighter, as they are larger than the mast they support (obviously!) You might consider, though, as you are a metal worker, the type of hinged mast that Needlespar made for some of the smaller UK boats. This had a very strong hinge that was made from solid alloy bar, let into the mast tube just below the tack of the sail, and a tubular alloy sleeve that slid down over the hinge after the mast was stepped.The sleeve carries all the bending load; the hinge is just there to make raising and lowering easier. This is the kind of tabernacle that makes most sense in small trailer-sailers, I feel.
At a guess, the mast tube is going to be in the region of 5in diameter.