[ADR]

comparisons to jetfins I think are a little tenuous. I had a bunch of pairs in my DIR tech diving days and they effectively have one way vents rather than holes that do nothing in the up kick but channel the water in the down kick. I have attched a jetfin pic so you can see what I mean. While the shape of the holes will make a difference the jetfin comparison doesnt really help us with knowing what to do next as they effectively have two surfaces to play with. Think of a yacht with two sails and the vent/hole effectively the gap between. We (to continue the analogy) have only one sail and are cutting holes in it....sorry but i'm from a sailing family