Haven't used that one Johnny but, beware! Most of the cheap valve seat cutters will only work on early heads. They won't even scratch the surface of the modern hardened seats such as on the TTR. I found this out the hard way.
I ended up buying a very expensive Neway kit which was brilliant. Once I had done all the jobs with it, I sold it and only lost a few quid.
My advice would be to bite the bullet and take it to a proper engineer. The angles etc are in the workshop manual.