I am a little confused on setting up a stepper as a spindle. I have the thing running but as far a setting rpm and motor tuning.

The manual states "Now move to Config>Motor Tuning for the “Spindle Axis.” The units for this will be one revolution. So the Steps per Unit are the number of pulses for one rev (e.g. 2000 for a 10 times micro-stepping drive or 4 x the line count of a servomotor encoder or the equivalent with electronic gearing).
The Vel box should be set to the number of revs per second at full speed. For example, a 3600 rpm motor would need to be set to 60"

I am using a 1.8 stepper with 10x micro steps so 2000 steps per revolution is correct. it says to input velocity at revs per second but the velocity box in the software says per minute . The motor says 1500 rpm "which may or may not have enough torque" but the velocity box will only let me enter up to 1050 at 2000 steps. According to the manual the correct vel should be 1500/60 = 25 and it runs way slow. Another layer to my confusion is pulleys. I have a 4:1 ratio so I have tried to set steps per rev to 8000 and still cannot enter a velocity # high enough. I have also played with putting the ratio into the spindle pulley setup. I can get this turning fast enough with enough torque to get the job done but I would prefer to have my math correct so that my dro will show me a realistic rpm for reference purposes.
I know this is a lot to type so feel free to give me a call
-Thanks