2 cents worth:
1] the only hurdle I won’t move (re: spacing) is the first; I will move the athlete if need be but its just my belief that visually that 1H needs to be at the right spot relative to the start line
2] within reason height is fair came; so far the “numbers” would seem indicate that it is more difficult for males to move “cleanly” from 39″ to 42″ height than from 36″ to 39″ height so on occasion I will use full height as there is sometimes a real struggle to move away from a jump at 42″ while 39″ is far more like a run for the same individual [personally I think it is almost forced since locally the transition from high school to university would mean for sure in 99.99% of cases skipping the first year of hurdling, not that that would be a bad thing, but won’t often “fly” w the head coach or with most athletes; transition here it is moving from 36″ in May/June to 42″ by late November and given how much time is lost for a high schooler in that time span of graduation year…]
3] can’t remember the last time TRAINING over 10H, 7H yes, 12H yes(very rarely) or more than a couple at full spacing (I am talking runs where the spacing varies); spend a lot of time w 3H or 5H or 7H outdoors in a foot to a foot and a half per flight;
4] exception in the case of an athlete who, for some reason, views themselves as unable to either clear a height, make a space or run the full race [first two less and less as the athlete develops, hopefully; the latter on occasion if the transition from 5H indoors to 10H outdoors is really, really short (calendar issue more than anything) and once they know they can, they should not expect to do much of it in training at all]