ChipFish,
Thanks for the work of putting these up for us all. Much appreciated,
And again Bill, awsome work!
You need very little surface area (size) in a side fin canted toward the stringer, to have a significant impact on board performance.
Bill
Hey bill are you saying the fins face inward rather than outwards when you say canted toward the stringer. Bit confused ???. Im a big fan of the setup and use it on all my personal boards, would be interested to know your thoughts on placement. 
Zackoopman. I think that’s exactly what Bill is saying. The outer fins having negative cant - leaning in towards the stringer rather than out to the rail as per conventional wisdom.
very interesting.
Aloha Zack,
As RDM pointed out, the side fins are angled/canted toward the stringer. It allows a stronger ‘‘bite’’ of the water moving rapidly up the face of the wave. It is important that there is NO toe angle to the fin. In my world it’s all about speed, drive, and turning, anytime and anywhere on the wave that you decide to. If you do try that kind of setup, you will quickly see that you don’t need much fin to get a strong input.
Bill
Tunnel fins “cant” in from the rails. Turbo fins cant inward. I wonder how small you could go on a sidebite if you put it right on the rail, like just inboard of the edge?
Smaller than you might imagine.
Bumping this up, for educational purposes. And, yes, I still have a few of those little side fins. Read from the beginning, for some perspective.
Start your reading with post #1, on the first page, and read to the last post on the last page. There is much to learn…about fins, thier function, progress, and innovation.
You can go pretty damned small out on the rail. A local shaper up here is a proponent of way out on the rail and fifty cent piece sized fins. I do think there is a point of diminishing return though.
A fin with a 1,75 inch base, and a .75 inch depth, provides significant hold when placed at each corner of a wide squaretail. ( Arc tail, and Diamond tail, too.) Point is, it doesn’t take much.
I use 1 1/2" single plug side bites on my daily rider that I get from Rainbow. I have also used them on Shortboards as a reverse “Twinzer”. Depends on the shape. I have two 9’4" boards similar outline different rail and edge at the Square tail. Both boards in waves to shoulder high do not need side bites. Once the size of the wave and the steepness of the face get right, the side bites go in. They are placed Hawaiian Style at 16 1/2 and 17" from the square tail. Center fin is six inches to the back of the box. I generally ride a Calif Rake of 7 1/2 " or deeper – 8" 8 1/2" or 9". My theory has always been that multiple fins on a board need to complement each. Not cluster f–k. Of course that is purely IMHO. To each his own.
The side fins in that first pic look as though they are toed out away from center at the forward edge?? Is it just the camera angle??
Camera angle only. The side fins are set parallel to the stringer.