I would disregard the cold/clean for now. Once you get a few more rounds on it, and your confidence in the load, then you will want to map the cold/clean and cold/dirty for consistency.
I may try this for seating based on your group. It may just suck them in tighter.
Load .010" (because you have that now as a start point and to foul if cleaned), .001" .003", .007", off the lands and see how it does. I prefer to move away from the lands if possible. Depends on how your .020" shot.
OR you could take the furthest you jumped and then seat deeper and try similar if it showed promise, but I would first explore the above.
***Also remember you are shooting an 8 twist, low elevation, high humidity. My SAUM and 6.5x284N both with 8 twist wasn't super crazy about the 156, but it drove nails with the 140. I am in Virginia so similar conditions.