Hi metjaf: I.can't answer you question, sorry, but would like to ask the same one to the Firewire Team - I've ordered the Sub Moon 9'5" for UK waters. The supplier is recommending - FCS PC7 Thruster fins, and I need to know if these really are going to be big enough on a 9'5" with 83 litres volume? I'm also interested in riding it as a quad, or quad with nubster fin set up, so will be buying 5 fins - just need to know which ones! Surfing will be beach breaks small to large, but generally mushy and weak. I'm an 82 kilo rider 6'1" if it makes any difference. Board not arriving till July, so hopefully have time to get it right! Thanks, Pete.
To me, the Submoon seems to be more on the performance funboard end of the longboard spectrum, than a single fin noserider. Surfed as such, i can't really see the need for anything longer than the 6.5 Kai Sallas and your two standard side bites. I use the same 6.5" fin on an 8'8" Dino Miranda and weight the same as you. I use a 9 inch Takayama RP single fin on a 9'6" Model T.
I hope to try one of these Submoons one day, depending which size you ride I imagine they would be very different boards.