To begin, here is my short board fin quiver along with more long streams of letters and numbers :
Left to Right:
VII F4 437, natural Composite
F4 437, old white plastic
FJC1 460, old white plastic
FJC1 460, natural Composite
VII FEA 450, natural Composite
VII Quad JC1 460 with 400 Quad rear, natural composite
VII Quad 1 438 with 375 Quad rear, natural composite
On the 7-4, I use the VII F4 437 vector fins.
The quad is too tight with the VIIQJC1 460 and 400 rear, but too loose with the VIIQ1 438 and 375 rear, so I use the VIIQJC1 460 side fins with the 375 rear. The 460 sides hold the face well, while the 375 rear allows more maneuverability.
I realize that the round pin tail on the new 6-10 is not going to turn like the quad squash I've been using most of the time, and the tightness might be partially due to me riding the thruster with too much weight forward. So yesterday I made a small change and went with the VIIFEA 450 (like m suggested) and got it on some clean faces. I was able to make some tight turns with the 450s without bogging down like I was with the 460s, while the down the line speed was still excellent. I don't know if the difference is due to the slightly smaller size or the VII concave inner fin surface that I'm used to surfing, or both. I'll probably stick with the 450s for a while, and try the 437s when we have a little smaller surf.
And scube, the 6-10 is a custom. I surfed a 6-8 Lost whiplash here and a 6-11 Rusty Surftech in Hawaii before I decided to go with 6-10. I wanted the rounded pin for 2X or so winter surf. My quad is 21" wide and the width was getting in the way on steeper faces, so Art & I decided to drop an inch of width, but retain the thickness for float. And finally, the quad is a little mushy in the turns, so I wanted to get back to a thruster setup to allow a little more snap off the top. Since I've only been surfing short boards for a few years, I'm expecting this board to allow another level of progression, and so far I'm encouraged. You're welcome to give it or the 7-4 a try when you're back in the water.
By the way, I'd sell the two white fin sets for cheap.
-HD