>>58751198Depending on which hole/pokemon you are going for, you can manip the shiny a little too. Not every spawn can occupy every area and the one that spawns first in the hole will always be shiny, so if other spawns are able to occupy a slot, you can reset until you get the one you want.
For example, I had a sewer level that always had a Cubone/Marowak spawn next to me. I could reset to get an Alolan Marowak and did, but I couldn't make it be a different family; meanwhile, I had a psychic zone where the spawns would move around freely (with some weighting, it seemed like) and could reset until my desired species occupied the slot that was getting the shiny.
Again, the shiny seems to always be in the same spot, so you just try that one place again and again instead of running around to find where it is.