No but I do not and have never used a back cut on the exhaust. Never even tried it. I agree with what he says about tulips as well and would have added that you'd want to specific throat shape for that valve also. I have a lot of experience with stock iron heads and they are limited on the exhaust and what you end up with is going for balance between a good number and port speed/velocity. There's a natural tendency when you get really really good intake numbers to push closer to the ideal exh ratio and that can diminish the velocity/a potential reversion susceptibility with a low lift enhancing backcut if you go by this literature/theory. They don't like to do much over 200 CFM they like to perform in the 175-198/200 range. Casting vary.. but the thing is.. they can flow in the 265-290's cfm quite routinely.
What does the fuel do when it hits the back of the valve with a back cut as opposed to with no back cut. That's a little more interesting to me at the moment because I'm not trying to use the wrong cam timing. We collect data when we flow ahead there's different things to look at. That data is very important when choosing a cam.