So I guess that is the another way, Dave. Start with scope fairly well collimated. Presume (??) the GSO focusser is fairly well squared. Check the laser dot is hitting centre of primary. Change over focussers without touching secondary or primary adjustments. Adjust focusser until laser dot hits centre of primary. Maybe monitor where the laser is striking the secondary for each focusser as well. If it moves substantially between focussers, that cannot be good?
Yes, and before anyone says it - the laser collimator will be well collimated itself.
