Which yields more pokemon - two active lures at once, or two lures used consecutively on one stop?

I've been curious about how to optimize my lure usage to get the most bang for my buck - or to ensure I'm not squandering the limited time you get with them, as I don't have availability to play all the time. From these questions it's clear that using two lures on two pokestops in range will increase the overall spawn rate. My question is this - is it more efficient to use two lures at once, or keep placing lures consecutively on a single stop?

That is, which technique will yield more pokemon appearances per lure spent, if any difference at all? If I see a lure active on a group of pokestops, should I place another lure next to it or save it for when the first lure runs out?

Using two lures at the same time vs. two lures consecutively should actually yield the same number of pokemon. The only difference is that you might catch a few more if you use the lures consecutively, but that's only because you would have the app open for 30 more minutes.

If you're going to be using a lucky egg as well to get double XP from catches, definitely use two lures on nearby stops. Otherwise, it's really up to personal preference.

You will likely get more effect from using lures consecutively, for two reasons:

1) Lures attract pokemon, but they also attract trainers. There is a good chance that another trainer will be drawn to the lure model, and will decide to use their own lure module on the 2nd pokestop.

2) There will be a slight decrease in pokemon caught as the number of consecutive lure models active increases, due to the time taken to catch the pokemon. Particularly if you are bad at throwing, or the pokemon are high CP.