My sister and her ex do 50/50 and it has worked fine for ALL of them.. I think what helps is that both parents live fairly close to each other, the schools they attend are both in the same area.
In the beginning the problems were mostly the Parents. My Sister and BIL were just awful to each other. If he needed to ask for her help, she chewed him out for changing the "agreement".. Then if she needed help he would just ignore her requests.. Then when he got married, she did not want the kids to attend the wedding even thought he kids LOVED the new wife.. Finally I had to remind my sister, "what are you going to do if YOU remarry and then HE will not allow the kids to attend your wedding?".. She finally backed down on that..
Here are the good things
The kids have their own rooms at each house.. If they leave something at the other house they are close enough to go and pick it up.. like school work or books.. They have learned it is their responsibility to stay organized.
We all live here in the same town, so if BIL needs my help or My mom or Dad, he is welcome to call us.
The kids friends can visit at each home, even spend the night, because they also all live close by.
The kids are now old enough that we also can get to them. My neice became very ill so BIL called my mom for help. My nephew needed to go to the dentist for braces, so we all helped both parents taking and picking up..
Bith my BIL and my sister can attend all of the performances, spots and other events without it being so far away.
As a child of divorce, her is my request.
No matter what happens, try to keep the grown up conversations to yourselves.. Do not rant or vent to your child about the other parent. Your child will always love you because you are their father.. and she will always love their mother, because she is their mother. When you speak badly about the other parent, you are forcing your child to defend the other.
I am sending you peace. Oh and, Congratulations!