I'm hoping someone can clarify something for me quickly, and my apologies if its been discussed I couldn't find it in the thread.
(1) If I go and add the degree circles (clockwise) to my ground board AND<Snip>
(2) So do folks first ID a known object, <snip>
(1) You can put the notch anywhere you like. Most of us find it convenient under the eyepiece. On my Skywatcher it is on the left side, and on my Coulter it is on the right. Makes no difference. With the notch under the centerline of the optices I can see this being a problem of sorts when trying to set the scope. May make it harder to see the settings, Other than that, it would technically work there just fine.
(2) Some folks are lucky enough to have their circles rotate so they can plop the base down anyway that is convenient, and they are ready to calibrate. Most of us have fixed circles with a movable pointer. Here is what I do.
Set the base so that my pointer is on 0 in the center of my range of adjustment. I have about 30 degrees of range of adjustment. I then point the base to where I know North to be. At the club fields it is easy as I know form experience where North is. At outreaches I use the compass on my phone to get close. Set it so that the front of the base, and this the optical path, is pointing North or close. I have +-15 degrees to play with here as I have a 30 degree range of adjustment. Your pointer, pointing to 0 will be in effect 90 degrees from North, but really it is showing that the OTA is pointing North, which is 0 degrees.
Now go to your favorite app, and find the first bright object you see. I typically use Venus for now. Bring up it's alt/Azth readings. Now center it in your eyepiece. Reference back to the Azth readings and with Venus still centered in the eyepiece put your pointer on what the app says the Azth reading is. So say they app says 212 degrees, put your pointer on 212. I typically wait for it to be a whole number or a half number (i.e. 212.0 or 212.5, 213.0, etc) to get better accuracy, but not totally necessary. You are now calibrated. No need to calibrate for Alt as a level level is well level.
Speaking of level, I do find it important to have the base level. I have a small bulls eye level I use that I hot glued to the base. So far when the bubble is in the bulls eye it is good enough.
Some folks say not to use the plants for this as their trajectory isn't as well calculated as the stars. So far I have not found this to be a problem in practice. When I do use the moon (careful of the sun it is still up) I do re calibrate once A bright star is up, but in all honesty this gets me close too as I can find Venus, Jupiter, Saturn and now Mars before they are naked eye when using the moon to calibrate.
After your done calibrating, just look up the object and dial it in.
Here is my cut out showing about 30 degrees of adjustment.
And here is what I use for levelers. They are glued where the feet used to be on the base. About 2" range of adjustment. Works for just about all but the larger slopes. I do carry builders shims and 1"x3"s but have only had to use those once to get the base level