newbie needs advice

Hello, I am in the process of converting my bridgeport mill to cnc
control, and have already purchased the ballscrews, and the drivers
(gecko) at this point I am looking at the motors, and am a little
confused about the sizes that might be needed, I have seen some
conversion kits with 1200 oz motors that are reduced 2 times. Does
this give 2400ozs of force??? what is the minimum size motor that I
should use? I plan on using this mill for hobby work with a small
cash job thrown in here and there. Thanks; John