I designed this mount for the Starrett 655-181 J-8 dial indicator for my Ender 3. It integrates a direct replacement back plate so it fits perfectly and has zero movement in the holder which allows for precise leveling of my print bed.

To use, I start with a 0.2 feeler gauge between my print nozzle and the bed (ie. set your correct z-offset for nozzle first). You only have to do this initial step once until you change out your nozzle again. To level the print bed, I zero the dial indicator to an initial bed corner. Once the zero point is set for the initial corner, I then go around to each bed corner to manually tram them to that initial reference corner height to ensure I get a perfectly level bed every time. No more using paper.

Print in the orientation shown with the yellow model (back plate facing down on bed) with supports enabled.