Symetrically foilled keel fins in a fish - how to set them up?

Hello there. I was hoping for some expert advice in the area of glass in fins for a fish. I have availed myself of a pair of keels that are foiled on both sides. I have seen these used in Dain Thomas fish with very little rake. I have also seen a very strange set up in a Van Straalen fish. Big cut outs in the back so the trailing edge can flex, no rake and the fins have no toe-in, they run parallel to the stringer! Is there someone out there who knows about this and can explain to me the advantages and disadvantages of both set ups? I must confess, I do like the idea of the flexing trailing edge. Thank you very much.

There is a ton of stuff in th archives about this subject… just type in keel fins and away ya go.

As far as I know;

Double foiled keels = traditional. No toe-in, no cant. I would assume you should set them perfectly parallel to the stringer or maybe toe them in a hair to avoid drag.

Single-foiled keels = a bit more progressive. Toe them in and cant them. I don’t know the best numbers for these, but it’s all in the archives somewhere!

…what jeremy said

Thanks fellas. I’m new at this. I didn’t even know there were archives! Is that my elbow or…?