Nameless Seer is Psychological Torture

Let me preface this post by saying I like the Nameless Seer mechanic. It is good, and it is powerful, and a very welcome change from Crimson Temple purgatory.

The problem is in its implementation and the obscurity of what influences his spawning. Over the last week, I've run a +100 quant Residence Map over 300 times (probably more like 300) and I've yet to see him once there. It's maddening, because it delays my actual farming strategy and what I want to be doing. I could just give up and move on, but the anxiety and FOMO of knowing how much better my farming could/will be once I finally do see him makes it feel awful. There's a sunk-cost fallacy running here now that's hard to get over, especially when you see all of these super helpful people telling us "I get him 1/30 maps". Good for you, but there's way more going on here than a simple 3.33% chance to spawn the Seer.

If that were the actual chance, we're looking at something like a ~1/1000 chance to not see him for 200 maps, ~1/10,000 chance to not see him in 300, and 1/100,000 to not see him for 400. At 400+ maps, the population of people who'd have this problem (and I see posts for them frequently) would so extremely rare there'd only be a handful of them.

...As I slowly typed this post up between maps, I found the Seer on Residence and have now scried him to Strand, and will never be caught in Residence again.
I had one last Residence Map left in my setup, so I ran that one quickly as well, and...guess what? Seer showed up again. That's 2x in a row after not seeing him for 300 maps. I'm glad this is over, pretty funny.

If this experience taught me anything, it's that I'd REALLY like more clarity on how this spawning works. I don't need to know the exact chance, just what does or doesn't influence it.

I've noticed magic monster packs have much higher chance to spawn the seer. Run 8mod maps with scarabs that add packs and Bloodlines scarab. You will find him very fast.

I think he works the same as reflecting mist, any monster you kill has a chance to spawn him. So just run stuff like ambush with chance to be openable again, giga-juice your maps to 8-mod with all the map modifier effect nodes on your atlas, all the influenced monster packsize on whatever influence you're doing and use scarabs for magic monster packsize and influenced monster packsize. That's how I got him in Burial Chambers, I think it took me over 100 maps during 2 days of farming or something.