Got some more dives in on my Eddys. I am so impressed with these. I've clearly adapted to them more and my frog kick is improving, but the propulsion they give from a frog kick is so impressive. What is it with the design of jet styled fins that makes them work so well for this kick? Couldn't be happier with them.
As for fit, I wear US 10.5 (EU 44) and got the XL since my bootie wasn't soft sole. Was a bit nervous when I 1st got them, because of the space at either side of my boot towards the back of the pocket and when out of the water if I shake my foot hard from side to side it move a bit. I noted that the tightness from the spring straps felt perfect though. Very comfortable and never felt like it could come off. I even tried to go one adjustment tighter just to see and that was way too tight. Importantly, in the water there was no movement during the stroke and they are comfortable. Again, couldn't be happier with this decision.
HTH anyone in the future.