QT: [to do threading at lower speed than my lathes slowest speed.] The lathe can only go so slow with the motor going at a certain speed and the gears and/or belts transferring that to the spindle.
Reducing the motor actual speed or with a smaller motor pulley would reduce the spindle speed but continue to produce the chosen thread.
Perhaps you have a 3600, 1750 or 1160 rpm motor. you can see by percentage how much slower the lathe might turn with a slower motor.
With a variable speed motor the thread would be still correct, but the lathe would go as slow as you select.
*But 50 /70/100 RPM should be fine with a little practice/skill. Or as some have suggested you can travel away from the headstock with an upside down bit, going reverse..
Your compound at 30 (29 1/2) allows the pull out to pull away from the chuck..going forward.
I put a piece of tape on my chuck OD to see that tape come to 12:00 - 11:00 - 10:00 - 9:00 and pull right on the exact spot every pull.
Good to put a cut off broom stick in a lathe and practice thread cutting. Mark a line on that and thread right up to the line.