My tip would be a GSport B&J 26.7 cm. I have used it with great success on both Carve 111 and Exocet Cross 106 (as the smallest fin) and on a RRD FSW 94 (as the biggest fin). It is swept enough to be loose, and has a wide base that helps with early planing.
And you can order it with a tuttle mount :-)
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