Here is the graphics I got some time ago from Tribal.
The leading edge is curved, but the base angle is actually over 46 and 47 degrees as you can see, and quickly gets over 50 towards the tip.
The red outline if the Slalom version and the blue is the Speed version (not sure if any of the 'Speed' version have been made just yet but if not they are quite close).
Mark Jordan has stock of the Slalom version now, or on the way and arriving very soon..
Shortest done so far is 12cm. There are a few Slalom 14cm fins out in the wild now and doing quite fast speeds.

This picture is from Mark. I think the top right is a 14cm.