Tuning really needs to be done with the motor attached to the machine, as the weight/inertia of the machine essentially acts as a big damper.

What Muzzer said about the basic PID tuning is the basic process.
Increase P until things go unstable, and back it off a bit.
Add some D which should then allow you to increase P.
Then once you find the limits of P and D, if needed you then add some I to reduce position error, but it will make everything unstable, so you then probably have to reduce P and D to get things stable again.

I'm not sure what other settings CNCdrive gives you, but once you've done the above on some controllers, you can then apply Feed Forward / filters to help further reduce any following errors.