Nail polish works the best acetone just don't wipe over the same place and start at the top and wipe l to r each time with a clean towel Terry cloth works your just taking off the oxidation of the plastic, the sun is hot man .
Another way to check for plumb is by assuming a man made structure in the distance was built plumb level and square. Say you're building a fence and forgot your bubble stick, you can plumb it by looking at a distant structure with your posts between you and the structure. It works well if the structure in the distance was built correctly.
5/16 - 8mm 7/16 - 11mm 1/2 - 13mm 9/16 - 14mm 5/8 - 16mm 11/16 - 17mm 3/4 - 19mm 13/16 - 21mm 7/8 - 22mm May not always be exact, but in my experience, my "conversion" chart has bailed me and others out a few times. 🤙🤙