The quickest thing to implement is probably installing a leech line. Just tie off a 1mm spectra line to the head grommet. Lead the line inside the tape and tie it off at the clew grommet. If it works well, install a web loop to tie off the line if you have to.

What do you mean by point? Going high to build virtual wind? I think it was Mike who pointed out earlier that if you dont hoist the spi to the designated height, it will be flatter than designed . The extra cloth have to go somewhere, and typically it is the leech. How about trying to hoist the spi until the luff is so tight that you can turn your fist only 45 degrees if you grab the luff, go sailing and try to point?

Was the spi fine to begin with, and did you change anything like mast rake just before you noticed this?