Hi everyone. So I have just some super mundane questions for everyone. I'm new to film so just need some pointers

1) I'm currently on a gig where I'm the mixer and boom op. Is it a faux pas to put my boom on a c-stand and run it that way to free up my hands?

2) Can you boom from below? Like if the shot is waist up and there's an ac vent can I boom from the bottom up?

3) I worked for a guy once who put his lavs off axis to the speaker. So basically if he micd someone's chest he would have the capsule pointing across the chest instead of directly at the throat. Is that a thing or am I misremembering or not understanding a specific technique?

4) Literally any other tips and tricks you'd feel like offering I am certainly open to hearing.

Thank you!