Hi Jeff
I used a 1mm thick Teflon. The stripe was about 2/3cm wide.
I first put it around the centerboard section, with thin plastic protection to protect and for glue thickness.
Then I positioned it into the hull upside down, and fill with charged resin, no glue at this stage, then after drying, you sandpaper and acetone it put the Contact/ neopren glue, and fix the Teflon without the centerboard first and then put the centerboard with some WD 40 in order that the friction does not move the Teflon.
After with a razor blade you cut the Teflon according to the keel line.

MK3 is fast in choppy water with strong wind, at least compared to Italian A Cat I used to sail.

Good wind

EK