The thread/pitch size of the DDM short shifter is M10 X 1.25. However, you may want to verify that with DDM. The Hurst shift knob came with several extra aluminum thread/pitch inserts, along with a locking nut.
I didn't use the locking nut because you could see it below the shift knob and used blue Locktite to keep the shift pattern in a north south direction. Even with the shift knob tighten down as far down as I could get it I still could see exposed threads under the shift knob, so I used Gorilla glue on the exposed threads and held the boot in place with nylon string until it dried.
I don't believe the Hurst shifter sits any higher than the DDM aluminum shift knob. In fact it might sit a little lower since the DDM shift knob is oblong. But DDMs might do a better job covering all the shifter threads.
Hope the info helps. Dan