Most new big booms have the pulleys for adjustable outhaul really close. I wonder if the sails rubs the adjustable outhaul lines when with neutral or negative outhaul (see the pic of latest Duotone boom) I tried to resurrect this thread but it was too old:
www.seabreeze.com.au/forums/Windsurfing/General/Home-made-wide-tail-end?page=1

I haven't looked that carefully, but from memory then even with a lot of negative outhaul the very clew of the sail stays pretty well centered at the boom end, once the sail is powered up, as there is always one of the three pulleys that is mounted in the center of the tail-peace. I guess the sail can touch the lines if the clam cleats are mounted well forward, but I don't think that it is such a big problem. I would have to check the next time, I know my sails are rubbing on the plastic clamp for the clamcleat though, so I usually put som clear mylar tape on the sails in that region (all the way up to the harness line position).

No, it doesn't rub.