The other option is to install a single point much further outboard, and sheet to there in a blow. The problems are, again, one of reinforcing the area. I'm also a tad worried about having to make an either/or decision about where to sheet the jib to on a particular day, and would be happier with a series of continuous adjustments. Has anyone made any modifications of this kind? Any suggestions on how we can do it?
My shroud tension system consists of 5/32 wire turned at the rail by substantial Harken wire blocks. These Harken blocks are in turn fastened to a bracket that is bolted through the rail. I already had small loops of wire (for the lifting harness) fastened to the cotter pin holding the block to the bracket. For Mounts Bay, we simply shackled a clam cleat to that wire loop, and rigged a 2:1 to a small block that floated on the jib sheet. I used a continuous line across the boat, so I could always grab it, and adjust the outboard lead on the leeward side. Sheeting a barber hauler to the shroud attachment worked well for us, but then we have a forward tack boat, so you probably want to lead your barber hauler further aft. None-the-less, rather than trying to fasten an athwartship track, a barber hauler just needs a turning block at the most outboard point (in this case the rail), so you probably get to mount it to a strong place. Then all you have to do is find an elegant way to lead the barber hauler line someplace where you can adjust it.
The only refinements I am looking for in my system are the leading of the control line and glueing some padding to the floating block (so it doesn't bang up the seat tank as much). The basic concept of pulling the lead outboard with a barber hauler worked find.
Where you have lead it to may not be as obvious as with an athwartship track, but you can mark the control line. I suspect the barber hauler will be lighter than the track as well (especially if you use incredibly thin line like Krister Bergstrom does!). You can move the lead outboard as little or as much as appropriate; you do not have to choose between one of two positions.
Now that I have this important control, all I have to do is figure when (and how much) to use it :-)