Many thanks, flyinfool! I did watch a (few...) YouTube videos and I got my precision level squared away, so to speak. I'm now working on leveling my lathe. Seems there's quite an art to this. I enjoy challenges!Definitely scribe lines, the angle change at the ends is from the scribe hitting the compound or getting to the where the surface ended.
You do not need a level surface to calibrate a precision level. there are many YouTube vids showing how it is done.