Side fins -- 5 deg or 9 deg or combo?

So I have a pile of FCS Fusion side fin boxes.  Some 5 deg some 9 deg.  I usualy just use the 5 deg boxes.  However I’d like to use the 9 deg boxes on regular bottoms without too much concave or vee.  I know I’ll get more lift from the 9 deg boxes, but is it an extreme difference?  Maybe put the 9 deg boxes on the outside and 5 deg boxes on the inside of a quad cluster?  Thanks.

9 deg. sides.

5 deg. rears.

Pretty standard Quad set-up.

Thank you.  I have always gone 5 deg on both for more drive.

My only gripe with the Fusion boxes is setting the cant - I don’t like a lot of cant and I find the 9 degree boxes to have too much cant except for boards with a real deep concave. I like 1" of cant (I measure the difference between the rear base and rear tips) and I can’t get it with either the 5 or 9 degree Fusions consistently without a lot of extra work. For side fins I prefer the x-2 plugs but I don’t think they’re as strong as the Fusions.

…in my opinion, FCS should do an intermediate measure. If you put a slight concave, 5º just do not work anymore for the sides of a thruster and the 9º is still too much with that bottom and others.

I can actually pull out my old glass-on fin jig and change the cant by +/- 1 degreee of the boxes before the tilt too much.  Often times I do tilt the FCS Fusion 5 degree boxes to 6 degrees, my old go-to for glass-on fins.  

…I do not understand.

According to fcs, the x-2 is the storngest system they offer as long as you install it correctly and doing the H-pattren.

…I normally use 4WFS and glass ons but yesterday I put a fusion 5º for the sides of a thruster with flat bottom and I tell you again that is not enough tilt for a sub 6 hot dog board. Then for full concaves the 9º is not so much tilt in the end and if I put 9º in a flat bottom is too much in most cases so again, I think that they really need an intermediate 7º to solve that.

Regarding tweaking the hole and boxes to get more degrees, is not good for the final impacts that the fins would get.

A little off topic…I’ve played around with Probox and TC Aqualine fins, for a combined 14* cant on the front of quad set ups. Created lots of lift and very tight square turns. Found it worked well in up to head high, steep waves with a short pocket. Lots of fun, but got a bit squirelly on bigger, gruntier surf.

Unfortunately, The Fusion system was designed when putting heaps of concave between the fins was the norm.

So many wide-tailed boards now with the long-forgotten Vee being shaped again.

I agree, they do need a 7 degree box.

I puposely route them a little deep so I can re-adust the cant to my liking.