Congratulations Bhank. If this works out as planned it will be great for all of you. Is there any flexibility in the ruling. For example one of you has a vacation planned that is two weeks long. If you and your ex are amicable, adjustments here and there will go well.
It is obvious from your post that you are really excited this got settled as it did.
My parents separated when I was very young, but not as young as your son. Even though they could not work things out with each other, neither of them badmouthed the other to me. There was never a formalized custody arrangement. Whichever of the two of them was in a better position to have custody, had it. They didn't get divorced for several years. Not until my mom married my stepdad. Neither of them paid alimony or child support to the other. I did end up living with my mom and stepdad through most of my childhood.
I thought about calling you "nasty names" in this post and then thought nah, your in a good mood for a change, why spoil it.