I actually run all nine machines from a RPC. Its very quiet and was the best solution for operating multiple machines. I use a 7.5 hp idler motor for the RPC system and have no issues. I added VFD's to the Plate roller and the lathe as I wanted more control and features. The Hitachi VFD's Im running are 240 3ph in.
If you decide to go RPC, just remember the idler motor should be of higher HP rating than the largest machine it powering. I ran all 3ph in conduit to machines including ceiling drops. The RPC can run all the machines at once as each machine that is turned on becomes a RPC for the next.
I chose to use cord caps so no fancy disconnects on each machine (except on the new lathe build). Plenty of information on RPC systems. I built my first system 15 years ago but with the new shop I found it much more cost effective to purchase the RPC control box from Phase Craft on
eBay. The guy will build your control box based on your motor specs. to include balancing capacitors. HINT! the better the quality of Idler motor the quieter the system will be. Again, my system is ultra quiet and the motor is mounted to the wall frame with isolators to prevent resonance (ask me how I know). If your only running machining equipment Lathe and Mill, then a VFD on each would be my recommendation as you will really like the speed control options and other control options they provide.
FWIW, I have $350 in the RPC system (not including conduit,plugs receptacles and wiring) so for multiple fabrication equipment thats the way to go. The new lathe system ran $2k in parts but the VFD was only $388.00 (USD).
I had a ton of help with the lathe system from an experienced friend, so I'm no expert but I have a firm grasp on each piece of machinery operating controls as I an the one that maintains and repairs them.
That is a real nice lathe you have.
The finished product!