SBM head velocities and there application?

Bewy said
Sounds like you have the Bettes book, a great book.

Nope, but sounds like I should get it.

Bewy said
I find that a lot of assumptions are made with some of the calculations, resulting in wrong final numbers.

That's why started the thread hope to get to the bottom of it, not saying anything I calculated above is accurate just a jumping off point.