What's the most efficient firework booster?

Well, I would say 192 duration 1 fireworks. Although duration 3 fireworks last longer, you don't have enough. Let's say you want to dive off a cliff every morning in Minecraft, and you use 2 duration 3 rockets every time (one there, one back). You can only have 32 flights, but if all you want to do is get off the ground and stay in the air, I say quantity is key.

You're using the same number of resources either way, but your stated objective dictates quality of firework achieves your goal.

64 duration 3 has the most propellant thus most distance (height) in a single shot before detonating; its like 3 fireworks (64*3=192).

Reddit users report a duration 3 gets you about 80 blocks, so more frequent landings with lower duration not only takes longer in a cumulative sense, but though resource use is identical either way, you effectively keep flight longer and faster from greater height with a duration 3

I believe that a duration 3 firework is the same as 3 duration 1 fireworks, so it uses less paper, but you have less control. So if you're fine with having a firework last longer, then by all means do it, but if you want more control, then use 1 gunpowder. you could also do a duration 2 rocket for a balance.