Another option that I have tried is the 'no spin ultra fin' (or something like that) from Maui Ultra Fins. It is a US box slalom fin that is claimed to be super fast and never spin out. I have found it to be moderately fast, does not spin out across the wind and up wind, but off the wind it spins out like a *itch!
The Venom is a superior product for sure.
US box Venoms are not a standard product from C3.
You have to ask very nicely ...