My lathe came without a plug. I selected the type that my welder uses so it would match. If you have or are getting any other 220v tools you may consider that as well as the amp rating. I assume you are building the box you showed earlier to use 2 x 120v outlets?
Robert
Your amperage will be limited to the house wiring. When you make a circuit using two adjacent breakers (as you plan to do) you are tapping into the +120 and -120 lines. The current flows from one black wire to the other (rather than from black to white.) Each circuit breaker will see the identical amperage by definition. If the house circuits you are using are rated for 15 amps that would be your maximum load. Keep in mind that home circuits are only intended to carry 80% of max rating continuously. So a 15 amp breaker should only be run up to 12 amps and a 20 amp breaker can run 16 amps safely. As you stated above the manufacturer says the machine needs a 15A circuit and therefore draws less than 12A running. Sounds to me like it will work fine.
Robert
For the 727 or 30, how many pieces can they be broken down into for trying to move downstairs into a basement? Manageable chunks?
Not sure what you define "manageable" to be, but the 30 can be broken down by taking the head off it's mount, remove the head mount from the column, remove the column from the base, remove the table from the saddle, remove the saddle from the base.
The 727 should be similar.