Are you going to run the Jib too? That is the only reason for the bridal foil. If you are not running a jib, I recomend you dump the foil and rig it exactly like the Nacra F17 w/spin. Use their angles and measurements. You need two lines at mid pole down to the forstay tabs, an anti gravity line up to the mast also to hold the pole up, you can then adjust the height to get it right.

I had a spin on my 5.5 Sloop, I tied the pole under the foil and that worked out about right for height, but you can adjust it down by tightening the pole tip lines to the bows.

You can see the tang angle for the bow forstays is different for the uni vs. the sloop, you can see the bridal foil wires do not line up very well with the tangs in the hulls, but I have seen other guys sail it like that and they didn't have any trouble.