Running it twice makes no difference to your EV (whether you are "in front" or "behind"), it only affects your variance ie. it makes the game less "swingy".

For me the decision on whether you want to run it once or twice is purely a stakes vs bankroll question. If you are playing a bit above the stakes you are bankrolled for, then in my opinion you should always try to run it twice.

In fact, you could argue that even when you are very well bankrolled for the stakes you are playing, you should always try to run it twice anyway.. PLO is a swingy enough game as it is, and imo anything you can do to reduce those swings is a good thing.

If you are a high volume player and want to lower variance as much as possible you can run it until there are no more cards :). In the long term, the result will be the same. You can't make a mistake by choosing to run it more than once.