Just did two tests, first was using the degree offset #99066=0 etc
It seemed to be working when I was cutting air but when I did the actual cut it didnt shift and just tracked the previous thread. This could be a smoothstepper thing as probably it is not implemented for the SmoothStepper
Next I did the Z start position offset and it again seemed to work fine cutting air so tried it on some stock and this time it seemed to work fine. I inspected it after it was complete and it looks very good, each start seems 120 degree out and pitch seems good for the full 100mm length.
Pic below is not very good but it will let you see hopefully.
Hood