Hi Particle!
I don't have a BOSS either, but I did stay at a Holiday Inn last night.
I have my knobs marked with , you got it, fingernail polish at just any point on the wheel. I always keep that straight up. Count, like opening a safe, how many times you pass zero and write it down. write down any variance from there to get to your smaller thread.
Reverse total adjustment when necessary.
I never have changed BOBBIN tension just top side to set the stitches.
If your adjustments are like mine you will be screwing in...why not use you red fingernail polish (you know..the Saturday stuff) to mark your larger outside setting, before you adjust, and just come back out the the paint?
Good Luck!!!
Kevin