All the other recommendations come from experience. I'm just starting. Take their advice. For example, my instructor recommended the BladeTech DOH.
I'll be using a BlackHawk Serpa holster (I already had) for a BB course in a few weeks. During dry fire practice I have to say the Serpa works really well. Trigger finger seems to naturally stay out of trouble. If it doesn't make the grade during the course I will be sure to leave a comment here. Of course if
I don't make the grade I will not blame the holster.
I was sad to see it fail in the video when snow jammed it. As he said in the video I think that would also happen with other types of debris packed in there. Too bad. I wonder if a strong, flexible rubber membrane over the button area would probably solve it. It would allow the press to disengage the lock without letting debris jam it directly. But that would raise cost of goods and manufacturing. Got any spare balloons