Z axis servo reduction gear

Hello,
I'm trying to decide whether I need a speed reduction on my Z axis router carriage design. The Z axis is powered by a nema23 servo motor from homeshopcnc,
http://www.homeshopcnc.com/servo2.html
and is rated 50 oz in continuous and 350 oz in peak torque. The acme lead screw is 10 tpi V thread and the nut is Delrin AF, the bearings are IGUS dry lin on 3/4 inch shafts. I plan on using the homeshopcnc 3 hp spindle at 21 pounds, so I think the carriage weight will come in at around 30 pounds total by the time the spindle is mounted in a clamp.
Is it possible to drive the lead screw directly off the motor with no reduction or would I be better off coupling the servo to the screw through a timing belt reduction setup to increase the torque and reduce the load on the motor somewhat? If it's obvious that I need a reduction what sort of ratio should I aim for?
Thanks
Denis