Smaller machine stepper motor speeds and resolution

HI everyone,

I am converting a small mill to CNC and have been considering stepper motor
speed and resolution of the z feed.

Its obviously a compromise using steppers, so you need to gear the feed at a
rate which is practical ( fast as possible) while not loosing accuracy
resolution or losing steps ( being under powered).

I have studied the stepper motor specs for the smaller 34 and 23 sized
motors.
They seem to get most torque at about 900 - 1000 Hz..

With a 200 step motor this works out at about 4-5 Rps (revs per second) ,

using a lead screw of 60 tpi and a 4 inch travel ( maximum) it takes about
60 seconds.

I am picking a 60 tpi screw for increased torque.

My question is this, from experience , what is the maximum practical feed
rate for small motors and what sort of resolution should I aim for ?

1/2 thou accuracy is ok for me !


Cheers

Mark