More of the same with a mirror. It's really tough getting that timing. The only reason I am still attempting to "perfect" this strange practice swing is that this same swing without the same exaggerated slowness from A3 to A6 seems to work pretty good on the course.
For me I doubt it saves anything honestly. Most courses near me don't have a distinct difference between white and blue or red and gold. There may be a few that it adds like 25 or 30 yards, and maybe one where it may make you pull a different club. Only one where I play a lot that's a huge difference takes it from 370 with a relatively easy shot to cut the dogleg over tall trees to 450 and no chance, where I'm likely playing 3 wood, 5 iron. I play back there against my dad cause I out drive him 40-50 yards easy and it keeps it competitive. He still smokes me around the green though.
But if it will take someone 5 shots to reach a par 4 green, it'll be roughly the same (maybe 1 shot here and there) when they move up.