Also, if you're ok with the possibility of more than one transaction getting accepted, you can shorten the wait to 66 seconds, if it's well-timed so that the transaction is broadcasted in the final block of the round.
The problem with doing this is if you're doing transfers, there's a chance that while one transfer is being reversed, and you move on to the next round attempt, both are accepted.
So 126 is good for attempting one-and-only-one transaction. Otherwise 66 is good, but slightly risky. And blindly spamming is probably also fine, but overkill, and not much more risky.