Mount for the Harbor Freight 1-In. Travel Machinists Dial Indicator, Model #63521, 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 (ie. back plate facing down on bed) with supports enabled.