James,
I agree with David that making your own sail is the way to go.
The mast for my 5.5m Broremann’s (10sqm) sail came out on exactly 10kg. An all-aluminium mast should come out 2-3 kg lighter, and thus be quite easy to raise manually and plonk into position, at least with the boat on the hard.
As for choice of tabernacle, I think that depends on how you are to keep the boat. If it is to sit on a trailer between the trips, one must make use of the easiest methods for handling the furled sail bundle. One method is to use a stub of tube for tabernacle, just tall enough to end about 10cm below the boom, when the sail is rigged. Before the mast is lowered after a sail, the sail bundle, batten parrels and all, can be lowered onto that stub before lifting out the mast. This shortens the time to make the boat ready, both before and after a sail trip.
Good luck,
Arne
Broremann's sail, part one
Broremann's sail and new mast, part 2