Recently, I had to finish several solid-wood doors I built for my home. I didn’t want to wait for one side to dry before applying finish to the other side, so I came up with this simple solution.
For each end of the door, I made a support from framing stock with a 19mm-square cleat centred on one face. Then I centred each support on the end of the door and drove in a few screws. The supports let you finish one side of the door and flip it over immediately to finish the other side. And the cleats help space the supports away from the door to prevent finish from pooling up at the ends.