Last 2 trips to the lagoon at low head the weed has been a bit annoying... Fine once your out in the river but a bit of it about close to the beach... so.....
With a donor fin on hand (Thanks Paul) I set to work at 1145pm last night and emerged from the shed this morning with something.... really not sure if it will work in the slightest, will keep you posted on that.
The direct drop from the board is 28cm. Actual fin length is 34cm. Angle is around 40 degrees.

If you get it right the weed fins seem to work OK. As you know I always use one and have found the board seems to be more stable with it. No spin-outs except for the ones where pilot error is to blame and I've never had any tail walking regardless of the size of sail or how fast I am going. I think the upwind ability is affected a little but if it means I don't have to keep clearing my fin I'm willing to compromise.