Definitely much wider rear spacing then you see on most boards. Probably why toe on the rear feels good.
Can you explain what you mean by not feeling the fins?
With the stock fins I feel like I'm mostly pushing against the fins in the turns on the wave, and that's not a nice feeling to me. With the added toe-in it is a bit like having "caster wheels" and I feel like I'm instead using the rail of the board to turn, this a much more surf-like feeling that I really like.
Other brands do have toe-in on both the front and rear fins. I think Simmer has about 1.5 degrees on the front fins and around 0.8-1 degree on the back fins (if I remember correctly) but I haven't tried to measure it on my simmer board. This means that all fins are sort of pointing a the nose of the board when looking at it from behind, similar to surfboards.
Select to expand quoteSurferKris said..
Toe-out would be very strange...
I have an older starboard 77l quad (from 2011, i think) with dead straight boxes and that didn't work well at all, to me. I could sail in a straight line with the windward front fin fully cavitating, while the other fins were barely being pushed.
Thanks for the info, i will give them a try asap.
I have a Goya custom 3, tri-fin, i am having similar situation, windward side fin cavitating all the time, sometimes making that spinout noise too. Unlike spinout i can't get it back to normal again. Is there a technique to make it stick again?
On my board it was worse on one side compared to the other. On closer inspection I found that one of the front boxes was mounted wrongly in the board, about 5-6mm too low, and the fin was sitting well too low compared to the surface of the board. I've since then made spacers to get a better match to the board on all fins, that helped some, but the real solution for me was to go with more toe-in on the fins. Now I feel like all the fins at grabbing, or letting go, at about the same time. Much like a singe fin will feel after a jump for instance.
You can see the spacers in the previous pictures, it is U-shaped and held in place by the fin. With each U-shape I can get two settings by simply turning it around 180 degrees. So the fin is either slightly aft or slightly forward of the centre in the box.
Besides the fact that my starboard quad fins came all bent, the quality and alignment are definitely debatable 
variable toe! Luckily for me I rarely go beyond 20 knots 
Select to expand quoteSurferKris said..
With the stock fins I feel like I'm mostly pushing against the fins in the turns on the wave, and that's not a nice feeling to me. With the added toe-in it is a bit like having "caster wheels" and I feel like I'm instead using the rail of the board to turn, this a much more surf-like feeling that I really like.
Other brands do have toe-in on both the front and rear fins. I think Simmer has about 1.5 degrees on the front fins and around 0.8-1 degree on the back fins (if I remember correctly) but I haven't tried to measure it on my simmer board. This means that all fins are sort of pointing a the nose of the board when looking at it from behind, similar to surfboards.
I have to measure extremely carefully, but yes my Simmer has some rear toe. The boxes are loose enough on the RRD that I can probably shim some to see how that feels.
Obviously it's a lot of apples to oranges with an 85L and 104L board from different manufacturers, but I like to experiment.
Definitely going to look at some 3 degree fronts for the RRD to see if I can get it turning better in thruster mode.
