I've bought the F3.0 (size 11.5) a couple of weeks ago and love them.
They are definately stiffer than my Deeluxe Rough Diamond. I would rate them smth around 6 maybe 7/10.
How much do you weigh if you dont mind me asking?
I kind of wanted something around the 6 mark, because I'm a solid 185 and I feel like I can flex boots more easily then someone say 165.