I have to do that kind of thing fairly often with the 6X6 wrapped porch posts. Usually one on each side at the top of the stairs leading up to the porch from grade level. I’ll use a hole saw to recess a 4" ceiling pan and drill down through the top of the post above the ceiling line then fish my wire down to the opening. I like to use a black button RX connector in one of the upper KO’s of the ceiling pan that are offset to the side, but not the center KO as that tends to get in the way of the fixture stud when using those shallow pan boxes. I will normally run each switch leg directly back to the switch location, so I only have one RX cable in each post to deal with when I make up the boxes and mount the fixtures.
