By the way, I purchased the Tectonics Tomcat 42 for my iS 111 and it is working great. However, the Tuttle head had to be sanded significantly to fit in the box. 0 spin outs in pretty rough chop with my 7.6 TR-4, and what seems like good speed. I haven't had the opportunity to test the top end yet, but we shall see.
The MFC fins - SL & RC have those little lines running through the fin material. I didn't like how they can be felt with the touch of the hand (not a smooth foil surface), plus I think MFC real strength is in wave fins, so I went for the Techtonics.