Backlash Comp/ Stepper motor tuning question.

Hi, I have a Harrison M280 CNC lathe, and I'm having a hell of a time trying to tune the stepper motors while using backlash comp, specifically on the Z axis. Machine is using a 77Volt DC power supply, and has standard cast iron bed ways and an ACME leadscrew and half-nut with about 0.045" backlash. When I configure the machine using PNC CONF(no backlash comp), I'm able to get the machine to traverse at 60 inches per minute and an acceleration of 12 inches/second². The machine is able to handle at least 20% more than that for both acceleration and velocity. Stepper drive timing is adjusted to be much slower than specified on the drives in order to reduce chance of having a problem. I've tried a Gecko GR214V and DM860A drive and the result is the same. Maybe someone with experience on a ACME leadscrew based machine can help. My experience level is beginner. Currently I'm going to test inductance and whatnot to get a better idea of what I'm working with. ini file attached.