Similar principles apply as in high wind FW, read this great article:
carbonsugar.com/technique/tuning-your-kit-for-high-wind/For foiling, there are some specifics, in my experience the following helps:
- mast base forward
- slightly more downhaul
- slightly more outhaul, depending on the conditions (assuming you've got adjustable system anyway)
- rear stab -2 to max -2.5? (that is, -2 spacer with 255 wing or 0 to -0.5 spacer with 255 -2 wing)
- longest fuselage
- counter-intuitively: try or keep large front wings, because they slow you down and allow higher angles (again, slowing you down)
- in any case, point as high upwind and as deep downwind as you can
- really commit to the harness
- have your harness lines perfectly balanced, and try extra long ones (38-42" max length)
- rear foot out of the strap (or remove the rear strap entirely)
- going downwind, rear foot is centered on the board and you sail unhooked
- jibing, take a deep and long arc, or plane instead of fly during the turn