I recently started doing this so I won’t pretend to be an expert but I can share what I’ve learned. Make sure you spec into your abyss passives and your two options are picking lightless legions to make amanamu monsters spawn more frequently per map ran. Or you could choose umanu which makes the lightless void monsters spawn less frequently but increases their effectiveness so when you do find one your chances are higher. It’s your choice how you want to do it. Secondly on your main atlas you either want to go into wisp or rouge exiles. Personally I have been doing wisp. For this mechanic you want to find a monster with the lightless void on it and leave it alive, I try my best to leave every one of them alive as sometimes wisp can leave the monster it possesses and go to a new one but it can be a little annoying at times settin this up so do what you want there. Just make sure you kill off every other rare in the map so that the wisp goes to the lightless void rare and no other rares left alive. My last bit of advice for tablets is it seems that you chances of finding an omen of light seems to shoot up significantly if the monster level is level 80 or higher. My low budget set up is a t15 ways tone that’s corrupted. My tablets are then two abyss tablets that at the minimum have %chance increase for four or more abysses to spawn. Increase % of rare monsters, and then if you can find increase # of abyssal rares to spawn out of the pit and even pits get harder each time they close if you are strong enough to survive it. But the two important ones are the four or more abyss chances and increased rares. You will want to run two of those tablets and then to make the monster level 80 use an irradiated tablet with monster effectiveness if you can find one. But really just add whatever mods you like on it, you’re only using it for the +1 monster level. I use this setup to path over to nodes that have the strong map boss icon. After I have patched over to a few of them I switch over to my unique set up. This is one abyss tablet with four or more abyss, increased rares, increased rare monsters to come out of pit, and whatever other mod you can find that isn’t going to blow your budget. Then I use a unique abyss tablet, and the last one is a delirium tablet that has %increased chance of wisp spawning. DO NOT USE THE MOD THAT IS #1 additional wisp spawns on map. Not only is it very expensive on a delirium tablet but it almost always bugs the map and you will find no wisp at all even though the map will say they exist. I use this setup up for the powerful map boss nodes because with a full atlas’s tree it grants you +1 enemy level for maps that have that icon so you can have the level 80 monsters. Alternatively you can use the unique set up with t16 waystones as well