Here's my suggestion, endurance for sprints or distance takes time to develop. The endurance you are training has to be specific to the race/events the athletes are required to run. Only the long to short method starts off with endurance and gets faster. A short to long or ends to middle approach takes the duration of the season and training uses that to develop the endurance. With the short to long you wouldn't necessarily do speed end or special end until the competitive season. With the ends to middle you would incorporate some sort of special/speed endurance 2x during the week.
Myself, I prefer more of a short to long and let the overall training volume for the season bring the endurance a sprinter requires up to speed, however I still have days early on were we TT 300m or some sort of intensive tempo at least 1 time per week. Acceleration and MaxV development are what I focus on early. The goal of the training is to have end of the season practices 2x a week that mimic race environments, with days where the runners run 80m-150m-250m-350m or 3x250m or 150 and 350 with very large rest periods just like a real meet. So the training is short to long but it has some ends to middle but 1 end is worked more than the other. I also find that the HS athlete holds up better and is less likley to be injured during the season with this approach even though it is very intense.
In a long to short program most of you will be doing more special 2 and tempo endurance work up front then working to special 1 and speed endurance. As has been talked about on this board the lack of time to do max V and acceleration focus in the training that you need very fast runners to begin with.