I just completed a tailstock die holder for my 12” lathe. There are several versions on the net and I attempted to incorporate the best features of each. The tailstock arbor is a standard purchased #3 Morse taper blank machinable arbor with added 3/4'” 1018 CRS slide machined and pressed into the purchased arbor. Two die holding bodies were made from 1018 CRS for a common 1” dia. die and a second one for a 1 ½” dia. die. A Tommy bar with knob was machined to turn/rotate the die holding bodies on the tailstock slide.
The majority of the time I would probably single point any required thread profile in the part I was machining but the die holders do come in handy on occasion.