Joe,
Thanks for posting your solution as i will put that into the manual somewhere.
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"Is it possible to shift the X origin (zero position) to the outer diameter of the starting stock so that setup operations whether using wizard or LazyTurn G-code are similar? "
Most all programs have X=0 as the origin for their code because it can be a repeatable place to easily find / reference to, along with a number of other reasons. There are a lot of ways of accomplishing what you ask. Depends on how "you" want to work and your understanding of Mach3 Turn.
For now here is MY suggestion for when in MACH3Turn:
Zero world X and Z which ( cancels any G54 so there are no offsets ) and set home somewhere away from the piece, move the tool "controlled point" to where the gcode for the part was created, click part zero X & Z, ( now machine=program=part cords at the same point ) move the tool to where you want to start cutting, cycle start the program and all should work just fine. That's a mouth full, but, just one way of working that will keep you out of trouble. I hope!

Depends on the gcode generated by each Wizard. I am not sure they are all a like on where the first move starts from. That said, don't let you heart be troubled, for there will be a section in the LazyTurn manual which will include information about Mach3 Turn.
prep moves from or to a point, including how to use use / create a tooltable, what impact use of using the tool tip radius vrs using the offsets which may have been created already. Program / machine / part coordinates relationships, how setting home can be used, an overview of Mach3Turn, etc etc etc.......whatever the verbage turns out / or needs to be. That will be put into the manual after the finish paths are available and whatever Art decides to do from a post processing point of view.
Simply put, I hope to cover Mach3Turn at some level in an appendix, the verbage will not conflict with the Using MAch3 Turn manual. The current four screens, are as they were created before my time, can be confusing if you don't have a good grasp of the whole program. I will see if i can capture the the compete program visually in about four pages or so.

RICH