Thermwood retrofit

I have an old thermwood C70 5 axis router. It hasn't run for 2 years now
because of controller problems of some sort. It has new DC Servo motors
that I think run at 90VDC and new encoders on it that were originally
thought to be the problem, but I guess not. I would like to upgrade the
controls and get it running, but the only experience I have is small scale
with converting a minimill over to run CNC using TurboCNC. One of the
issues I see is that the gantry moves using two servos and two screws for
each side. These need to be run together and the same time and speed
otherwise it will put things in a bind. I think the servos are rated for up
to 120VDC and at least one was a 4.7Amp servo. The original software, if I
am not mistaken, also was calibrated with a table of some sort for each inch
of travel compensation. The way I understand it, it is calibrated using a
laser and the discrepancies are entered into a table and the software uses
this to increase the accuracy over the long axis's. Does anyone have any
experience with a retrofit like this or can anyone tell me what the best
route to go on this thing would be?