I have worked with the AutoTurn during the development process. I have no financial interest in what they do at Putnam but do recommend it as a great solution for CNC'ing your lathe. I use the equipment with my mini-lathe and a 10K South Bend machine.
The AutoTurn performs as advertised. Putnam can supply or recommend a power supply and motors. Your lathe sounds large and will probably require their large driver box. They also have designs for stepper motor mounting brackets for various lathes. I worked on some of those designs.
Get in touch with them. The engineer, owner, Charles is very helpful.
Rich Vanden Berg