I grew up on the west shore of Michigan & I agree that the waves out there are different than waves in the ocean. I think it has to do with no tide (wind only) and the sand bottom, rather than some kind of coral. I have paddled all 3 of the S6 models and currently own the F. I think you would have a great time with either the F or the standard S6; however the F is shorter and may be easier to deal with the steep faces. I think it has more rocker too and that should allow you to lean forward to catch the wave with less risk of dipping the bow. I don't think speed is as big of an issue as many make it. I have surfed all over Washington and Oregon in a Pop - a very slow boat - and never felt like I needed more speed.
By the way, where are you in MI?
Try not. Do, or do not. There is no try.