That’s a pretty useful discounted hurdle timing conversion, I used to just compare the times to similarly discounted runs when I was timing myself in practice all the time last year.
I start at 30cm, and move them out 5cm about every 2 weeks. It’s quite possible that I could just start at normal distance, but in the past it just feels sluggish, especially in the November/December time frame, when I’m only working on acceleration.
As for individuals, I can’t speak with much credibility, as most of my experience is from my own workouts/experiences, and I have limited coaching familiarity. I would think that the difference between race height and a lower height wouldn’t have as much of an effect on women’s hurdles than it would on men’s. For a 5’10” girl, 30″ or 33″ would still be well below their inseam, whereas I would think that a 6′ guy would have to raise himself up over 39″ a little bit (I’m 6’4″ so not entirely sure).