Thanks for taking the time Roger. I have an 11.0 Sailworks Retro and have been learning to pump it however, have not pumped the fin (didn't know that this was possible!).
From your comment about the Start being able to take a 78cm fin you believe that the Techno Formula will not. I have been trying to locate a used Starboard formula board for my weight (like the 2002 F-186) but have had no luck. I have found a Techno Formula and just assumed that the 3kg weight saving would make a huge difference. Thanks again.