Mike,

You are correct that a hit slightly less than 1/2-ball is required for equal separation angle and speed. FYI, the physics/math proof can be found here:
http://billiards.colostate.edu/techn...ew/TP_A-16.pdf
This can also easily be shown at a table.

You are also correct that at faster speeds, the CB will be delayed slightly due to the time it takes for the CB to curve forward from the tangent line per the info and demos here:
http://billiards.colostate.edu/threa...ion.html#speed

Regards,
Dave

Dr. Once again thanks for all you do,and have done.
Need a little help with..on a 1/2 ball hit with running english,will both the object ball and cue ball arrive at the rail at the same time?I believe a slightly less then 1/2 ball hit is required for equall Timing? I believe the harder the collision,the bigger the time inequallity becomes?
Thanks again,Mike Filholm