Each system is different, it all depends on motors, drives, weight of axis, pitch of ballscrew, geariing etc and unless someone has an identical machine in every way they cant tell you. Best thing I have found to do is set the acell low and start increasing the Vel testing all the time by using the Up/Down arrow keys. When it starts to miss steps (motor squealing) back off a bit. Then start increasing the Acell until the same happens and back off. You may find it is better for you to have a lower Velocity and have the Acell increased, all depends on your individual machine so its trial and error I am afraid.
Hood