Z height adjustment made easy: When you really need to dial in on the exact "Z" height, it is best only to have to deal with one screw, instead of 4 under the build plate. In order to do just that, I've made a new endstop holder so that I could fit an adjusting screw onto the X-axis gantry. Turning this screw clockwise raises the extruder and not the build plate (counterclockwise lowers it). My M3x0.5 allows me to know the exact amount, for example, 1/2 turn equals 0.25mm. I use a dial indicator mounted onto the extruder bracket to level my build plate without concern about the cap between the extruder and the said plate. Once the build plate is level, I simply adjust the required distance by rotating my one screw.