Ok me and my friend have done a number of sessions today trying to farm these DRK feet, the first time we managed to find one with 144 amber, but we would get a ton of bigger chests and/or smaller chests with powerful/temp/key item boxes.
It seems at amber 144 you get much more key item drops, i was the key man so this seemed like the trend,
After trying again for a second DRK feet, we decided to try it with Amber on 128 this time, after an hour of doing this, we managed to see one RNG feet, but gold chests were not frequent enough, we got one more amber light and got it to 136.
Immediately we had a huge flow of Gold chests, we saw multiple feet drops, although we were still getting some of the big boxes it was not as frequent as 144, also in small and big chests the trend to me, seemed like we would get Items(not powerful, temp or KI) from these chests more frequently then any other.
I believe, and this comes from actual testing, on Colibris in Misereaux with just a THF/NIN and a WAR/DNC, that 136 Amber with 150-230 Pearl lights is the sweet spot for farming Feet in this area.
Colibri will link with others, but they do not aggro, they also have about 4.5k-5k hp, so we were almost one shotting them (using 3 atmas like RR/VV/Apoc or RR/VV/Sea Daughter), they do not have any nasty Aoe moves, enfeebling moves and we pretty much stayed alive due to temp items and /dnc curing waltz, we could kill these nonstop even if we had links of 3-5 birds at a time.
To proc Amber on THF and WAR, we used Aeolion Edge and Heruclean Slash(GS) in the last 12% of a birds life.
I hope this information may be helpful to anyone who finds themselves wishing to farm Feet in a low man situation, do not get Azure lights, do not get Ruby lights, there is no need to get silver/ebon/gold lights, make sure you both have Elemental weapon skills on your job so you can build amber lights, you will be good to go, happy hunting! :)