First order of business was to finish getting the vents free from where they had been glued in. Not too bad a job with the first vent done as a test run a couple days ago. Then I trimmed out the openings in the overhead to their final size. The overhead was clecoed in place, which revealed that the oxygen plumbing interfered with the overhead speaker, so I freed up the clips in that area and laid the overhead in place. With it in position, I aligned the covers and matched drilled them #40, later to be replaced with nutplates and #8 screws. Then I drew the outline of the overhead on the cabin top and, using that as a guide, repositioned the oxygen tubing to clear the speaker. Finally, I measured the runs for the electrical connections to the oxygen system, with the plan to ask Aerotronics to make up the D-sub ends for me.