Thanks, Roland.
No, my friend has logged hundreds of hours spearfishing in the Sporasub Dessaults--which is the fin he recommends.
However, since I'm new to longfins, he was thinking that, since he is ordering a suite from there, throw in an inexpensive pair of fins until I have time to really figure out how much diving I'm doing, and under what conditions, and what fin really works for me.
My philosophy is a little different--which is, do a lot of reasearch up front and at least get something good, even if you end up selling it on ebay later. By the time you've spent $50, you might as well spend $100, in my thinking.
So, thanks for your structural analysis, that's very helpful.
--Clinton