Anyone have experience with this fin on single fin performance longboards...especially rounded pin tails. I know they are more for V-Bottomed classic longboards
That's quite a resurrection...
I had good luck with the Velzy classic on my lighter weight HPish longboards when I rode them as a single. Pretty much always round pins though I recall a square or two. Noserode fine, turned fine, but in the end I liked something with a bit more of an upright profile for a higher performance single - seems to cut the turn radius for me, and easier to hit the lip (the OP specified HP!), especially in smaller surf.
I've always liked the Velzy fin with its reduced area, yet still adequate rake. I don't like fins with too much area as I feel they stiffen up a board too much. I don't think upright pivot fins work well on pintails, where you tend to draw out your turns so the Velzy fit the bill perfect.,