Don't mean to hijack this thread but do you have any experience with the Eddys?
I'm also trying to find my perfect fin and the Eddys, SP GS and Quattros seems to be amongst the top.
Does the GS give you same propulsion as the other ones?
No, no Eddy experience. I put my Quattros away after I started using the SP GS. I'll use the Quattros as spares or for use in training. GS did give me at least as good propulsion as the Quattros if not better (it is subjective) while being more comfortable and less bulky.