So...
Looking over the files on cool self-steering solutions I came across this vane retrofitted to an RVG gear and I like it! I wish I had had the opportunity to chat with the owner of the boat but we never did catch them onboard.
Anyway you look at it, this is a very nice vane.... and I am pretty sure that this is the general direction I'll be working on.
On our old RVG, I never had any complaints with the amount of rudder area but did feel that the trim tab could have performed a bit better with a more refined foil shape.
So the next job on the list is looking at the trim tab foil...