Min Dim = the dimmest the tubes will ever get (when the LDR sees total darkness). Experiment with values like 100 or 200, put your finger over the LDR if practical, or turn out all the lights If your tubes look bad (flickering, partially lit numbers, etc.) use a bigger number for Min Dim. The perfect number depends on your tubes and what you like. I run mine at 200,
PIR Timeout = the time, in seconds, that the tubes stay on when the PIR sees no motion. Default is 300, which means the tubes turn off after 5 minutes of no motion.
Look into it later when the dust is clearing off the crater.