Not sure how to answer this one.
It is good at dissipating heat, but there is no cooling fins so i would not use it on high till the battery runs flat, generally with most high powered lights you need active cooling like walking or moving around, i use fans to do this for my if i do run time test's or i go for long walks at night.
To run it on high for 8 hours you would need 4 to 7 batteries for each light and to get the Maxim run time like that you would need to spend around $13 usd on each battery then need a charger to suit if you don't have one and i don't think many XML torches could do that at all.
I think 3 hours on high and 5 hours on low is to much for most XML lights you would need a pile of batteries and you run the risk of cooking the led or driver, to replace the driver is under $5 usd and to replace the led is under $9 usd and then you need equipment for the repair.
Medium mode is around 60 to 50 % at a guess as i have not measured it, maybe others can chime in here.
I think the POPPAS W-878 has huge flood and is good for the price i payed, every one Ive showed it to has been impressed by it.
There is other lights, there is 2 that i have personally used that can run from 2 to 3 hours on high or run 8 + hours on medium or low and still give out good light to light up a room, but they cost $35 to $55 usd each and they both need 3 x 18650 batteries each to do this and they would need electric fans to blow air on them to help keep cool or be run in very very cold temptress, like a refrigerator or ice box not like Singapore, i could buy a generator cheaper here then i could buy 4 to 6 torches, batteries, chargers and run them 2 or 3 times a week.
Maybe make a post on in the forum asking for suggestions, i know there are lights are there that can run for days on low mode but will not put out much light or heat and use cheaper batteries but i have no experience with them, so i have no idea.
If i was you i would be looking at lanterns, big candles, gas or kero lights or a generator as using XML LEDs to do this job is going to cost to much and not give you what you need.
I wish you all the best with your lighting issues i hope it works out.