I’ll resurrect this thread since it has so many of my observations already. I didn’t work for a school this year, but I did work with a couple kids at the request of one of my mentors. The most notable was a senior boy who had struggling with his 3 step. While we also made a couple technique changes, I think the biggest difference maker was the addition of speed drills starting with 30″ hurdles. I worked him up to the 36s in a couple days and he dropped his PR from 17.8c to 16.7 FAT the next week. His season ended the week after with a 16.6 PR but I’m pretty confident he would have run close to 16.0 with another week or two. He was running that well in practice, he just didn’t get a chance to do it in a race.
The other kid dropped her times a second as well, but that was from switching her from a five step to a four step, and getting her to eight step the first hurdle.
I bring up this anecdote because I think it reveals a critical time frame that it takes an athlete with good technique to transition to good times. This particular athlete didn’t adjust as fast as some of the kids I’ve coached, so I think if you have an athlete you are trying to get into the 15s, getting them good technique 4 weeks before you need them to break 16 should be enough.