hi everyone , i have a question if someone could help

i have a acra knee mill i want to convert to cnc ,i have posted before about this when i was looking into doing it about a year ago but only now i have the time to do it
i have done my research in relation to ballscrew gearing ,critical speed of the ballscrew what servo motors and other things as well , i have decided to go with a 5mm lead with a two to one gearing and 750 watt 3000 rpm servo motors and achieve about 7500 which to me is fairly fast for a knee mill and i most likely won't be able to rapid at that speed due to being a knee mill so i thought that combination would be ok and at 3,000 rpm not to reach the ballscrew critical speed and still have fair speed
my question is if i was to use a 10mm lead with 3.1 gearing with the same servo motor speed, instead would that have an affect on the resolution of the machine considering the encoder works over 360 degrees
meaning will it affect the accuracy to achieve a rapid speed of 10000 and be able to lower the ballscrew speed to 1000 way under the 2000 critical speed for a 25mm ballscrew

thanks in advance
kind regards wayne