Good for you for trying to master indirect vision. Many of my classmates have given up and just position the patient on his/her head while the lean over and try to look in- they'll make their chiropractors very wealthy in five-ten years. We had an entire class on ergonomics so it really sucks your school doesn't offer this.
When working on the maxillary, the mx dentition should be perpendicular to the floor. As far as chair position, I'm most comfortable at 12-11 o'clock for every procedure. Sometimes, I swing around to 7 o'clock to reduce the lingual of quad III when cutting crown preps. If you get used to working with your mirror, you really don't have to move around a lot. And don't forget that the patient can turn their head away or towards you (unless they have a neck problem). Don't hesitate to ask them.
I usually set my mirror at the patient's lower lip (when working on the mx) When using a mirror, you can get disoriented easily so I like to trace out my moves before I hit the foot pedal. The long axis of mx teeth are pretty much straight up and down so you don't have to worry much about angulation (ie. when cutting a class I, line the bur straight up an down to the occlusal surface and make your punch cut).
If you don't have loupes, get them. They make everything easier and quality goes way up. Lower the chair to where everything is in focus in your mirror with your loupes. You probably may still have questions about working on certain surfaces of teeth. Ask a hygienist. They have to work on every surface in the mouth every day all day (to probe, clean etc). They can give you tips about how to position your patient and yourself. Hope this helps.
