Aside: funnily enough, I actually caused the double block

Of course you can't cause a block on purpose, only in hindsight.
I sent the 407467 payout, when I awoke in front of my PC, and the next work item, with that transaction, found a block less than a minute later.
I sent the next payout 407468, a few minutes later, and the next block, with the payout in it, was 10 minutes later.
I was sure happy about it at 2:15 in the morning

It's good to know that you had a hand in the double block...even in hindsight. All I can say is...do it again!