I say go with the hoops, but it is a more expensive system. you will
need shackles, lacings, and hoops. Sail tension is a lot easier with
the hoops. But, if you can get your hands on some good 6" schedule 40
pvc pipe, you can make your own with a hacksaw and some sandpaper.
Size of the spar would matter too. on a short spar, I would probably
go with the lashings. Birdwatcher II's rig looks as if it is the best
of both worlds with the sail being lashed to the upper spar and then
the spar is hoisted in place. The sail is not fixed to the mast except
at the tack. Can't remember the actual term Bolger used for the rig,
but will check the plans this weekend. Spars are underway...