You should use as high an acceleration as your drive system will allow. Since it is totally a function of the drive mechanics and motor capabilites running at the applied voltage there is no way to tell you a specific setting without a lot more information.
The reason you want good acceleration (expecially for cuts with lots of directional changes) is that the sharpness of a corner or angle is determined by the acceleration. The physics of cutting say that to change direction you have to deaccelerate then accelerate again. In order to try and keep the machine from jerking the control tries to smooth out the stops and starts. It does that by rounding corners. The longer the acceleration curve the rounder the corner.
The tuning of steppers is a balance of RPM VS Acceleration. You can run the the motor at a lower max velocity (RPM) and gain better acceleration numbers and vise versa.
Start with accel numbers that are 2 to 5 times the max velocity (in the same units: IPM/sec) Keep raising htem until your motors start making funny noises and loose steps. If you are happy with the max velocity then back the accel off to about 80% of your test level. If it's too low then you will have to sacrafice some of your velocity for higher accel numbers.
The mass of the gantry, the size of the motors, the belt reduction ratio, the applied motor voltage and other factors go into the max velocity and acceleration you can get from a system.