Thanks, Think I have it
I had a Boxford 160TCL and now the larger 240 so working in the same co-ordinate system space as you. So know the mental gymnastics, of having a "rear" tool-post, reversing the arcs, M4 turn, M3 drill/bore which is actually not inverted, since these are TCL and which to show the operator the cutting action rather than clear swarf with a proper inverted tool. Happy with a M4 parting tool. I guess if you stick to programming only lathes of a similar style then this not an issue and do the mental flip that as CW view, draw and note the tool geometry from below. I will programme a few more simple parts, cut some air and then some soft Aluminium and reinforce the learn by doing.
Have you used a fixed tool position on the lower end of the X slide ( the early 125 had no turrent, just a tooling array on the cross slide) and so cut conventional in front of the stock with M3 ?