The best bankers hit most shots very firmly. That is also recommended in the tapes by Bugs, Freddy, etc. In truth, you need to know what speed to choose to make certain banks in addition to the correct spin. Speed generally stiffens (shortens) the angle and rolling or shooting softly widens or increases the angle. Draw or stop generally stiffens as well, and is used a lot.
I highly recommend "Banking With The Beard" especially. Just to be clear, that is the first book Freddy wrote. The sequel, "The Gospool" is good too, and has more entertaining stories, but the first book can't be beat for banking instruction and secrets. The DVDs have many cool shots but the first book is the nuts...Tom