Maximizing Runtime+Brightness Among Multiple Lights

If I have multiple copies of the same light that has multiple modes of brightness, how do I best maximize their runtime and provided brightness: in series, or in sequence?

To clarify by example: Assume we have 3 Streamlight Siege lanterns. Each runs off of 3 D batteries, and its manufacturer ratings for each mode are: High (340 Lumens/30 hours), Medium (175 Lumens/70 hours), Low (33 Lumens/295 hours). Let's assume each is topped off with fresh batteries, but we have no spares to recharge. A power outage occurs and we want to provide bright cheery light for as long as we can so that people can see well enough to eat, read, or play games in a small common room--we will assume that while the outage will be an unknown amount of time to fix, it is not a true emergency situation and we don't want people to have to curtail their normal activities by going for a true maximum runtime of only a single lantern on low.

Considering that power consumption per lumen increases linearly but perceived brightness per lumen only increases logarithmically... and that running multiple lanterns at once means the batteries are being consumed at 2 or 3 times the rate... is the better option to accomplish this task going to be having all 3 lanterns set on low (and, I expect, evenly spread throughout the room), or having a single lantern set on medium or high (which could be alternated among the 3 to rest the batteries) set/hung in the center of the room?

Or to phrase it more simply and generally: is it more efficient to run a single light more brightly or to combine multiple smaller lights to produce the same amount of perceived brightness?

It would be better running multiple lights on low if they end up being bright enough for your needs. As you said LEDs are more efficient at lower drive levels. Alkaline cells are MUCH better at lower drive levels. So the lights will give more lumen per watt and the cells capacity will probably double

I think Low will always be better.

I find a single Siege on Low to be too high many times so we each have different levels as a minimum to keep things Cheery I think.

I also compared the Siege and UST lights and found the UST to have a much more comfy warmer tint to me so I use those now which makes the whole experience better too.
I am not sure they are as nicely made as the Siege but the light is a lot better to me.

No Red but not a factor to me at all.

Candles increase battery life tremendously. So do mirrors around said lighting products. Mirrors can also direct light for instances of say reading for example.

But back to the original question. If a low setting puts out say 20 lumens for lets say 12 hours in the case of a single cell light which has a 2 hour runtime of say 100 lumens then 3 of them at potentially 12 hours should certainly provide enough lighting for most conditions cited and they would be good for likely 2 whole nights of lighting assuming folks stay up all night. This also assumes there are windows letting in sunlight.

In a bunker for example max runtime should always be first priority and folks will just have to squint. So things done for entertainment for example should be brightly colored board games vs say a dark brown and black backgammon board.