Mini-trailer for twinnie?

Had my mr-style twinnie out in a solid (freak) 6’+ swell last tuesday morning, and it was just a hair too squirelly. I was thinking of a little trailer to help it track just a tiny bit better in critical situations. But one that wouldn’t take very much away from that slippery looseness that’s so fun the rest of the time.

The fins in the board now are about 6.25" base and height, and like 9 or 10 something from the tail, I think… Sorry, too lazy to check.

I know there are quite a few of those MR twins around with the teeny little trailer on there. Was just looking for suggestions on size and placement for a bitty center fin that I won’t even know is there until I need it.

Maybe like this:

I know there is a world of variation and subtlety, but I’m going to glass it on and won’t have the luxury of an adjustable box to fiddle with it… So, some good guidelines would be nice. Especially wrt distance from tail and height/base.

Thanks!

We used to glass on a 1.5" based, 4.5" tall finger fin about 4" behind the base trailing edge of the side fins. Solved in squirrel problems and still allowed quick twin style pivots.