Noice Sue That glass is looks sooooo good.
Something I noticed and can't explain: In the below screenshot of you mid gybe, there is no obvious turbulent wake coming from the the FF24. Is the weed absorbing all the turbulence before it can get the surface? Have you got any other video using a different fin to compare it with?

That's seems pretty plausible Decrep. I have just gone back and had a look at my videos and the same thing happens, I just never noticed it before

I probably do have other gybing footage with another fin but haven't had the chance to look at it all yet..ugh..got to work sometime....Sounds like it's normal though?
I found the 24cm FF a bit big that day and was bogging down in the gybes on the weedy side.That spot had patchy wind earlier which didn't help things as the wind increased it was getting better .
I think I only got one decent full planing gybe on that side and that was as the wind increased..but then I had to go to drive home..
If I had stayed I would have put the 80ltre and 20cmmFF on and I'm sure that would have fixed the problem..