What's the most efficient method?

[ayydreeinn]

I know 2FA codes change every 30ish seconds, so its by pure chance you get the actual code.
But for backup codes, they dont change, but its a combination of 8 numbers and letters, thus resulting in a more clearcut result, but more time to find it. Does anyone recommend a method? Currently running login and normal

[Derpitron]

normal is the most efficient mode.
normal has 10^6 possible combinations.
backup has 36^8 combinations.

10^6 << 36^^8