Ours was pretty much decided together... Quite shocking actually.
The mediator determined how many hours a week he got with her, which was 18.
I have primary physical so I make like day to day decisions.
But we both make decisions as far as schooling, medical.
As far as holidays, We agreed that I would coordinate it. As long as he got his birthday and fathers day with him and I got mothers day and my birthday, but that was mainly determined because originally he had set days with her so if mothers day or my birthday landed on those days, i got her.. I've always been good about including him in holidays so it hasn't been an issue. I didnt want anything set and then it not work later on or when the time came.
As far as 'rules' the only thing we agreed or were determined was that he was not to smoke around or while he had her and that he has or carries an inhalator for her (she has severe asthma)
All I know is its better to come up with something together then to be completely non-negotiable because then its left up to the courts to decided and you both might get screwed.