How do you stop the weed from getting caught in the overhang in front of the fin box? I have the luxury of being able to leave my fins in when not in use. Of my 4 boards I have tried 4 different methods.

1 Stuck it in with dingstick (no weed) 2 Tried to get the best fit possible by sanding fin box etc (some weed stuck) 3 used sickoflex on a Fangy Fin (seems to be working ok) 4 stuck it in with Araldite (not tested but looks ok and I did this on the oldest board)

Surely there must be a better way that works evertime?

The Delta XT has that bit of shaped high density foam under the overhand that seems to work ok.

had the same problem with a maui .
i cut a piece off the fin cover and glued that on ,it never happened again .
make sure your fin is in tight ,maybe grab another washer .

Sikaflex polyurethane sealant

If you can slide a 0.05mm feeler gauge in, it will collect weed.
A lot depends on why the tip isn't touching the board.
If the fin is loose in the box, the rear screw is pulling the front of the fin away from the board.
You can fiddle with the fin to make it line up better, or pack the bottom of the box at the rear, then the front screw will pull the front of the fin down.
If you have my problem, of a finbox leaning slight backwards, then the base needs packed at the rear top and the front bottom. Or the angle of the overhang needs to be modified, ground away near the base, tapering to the tip

Try 3M sup rail tape. Cut a section slightly larger than the overhang, stick on and press for a couple of minutes. Then using a new sharp box cutter blade trim off excess. Add layers if needed. Cheap and effective.