My daughter has had a 50/50 arrangement since she was 4 1/2, she is now 9. This has worked well for us. My schedule with her is:
Week 1 - Sun, Mon, Tues, Fri, Sat
Week 2 - Tues, Wed
Repeat
Any type of arrangement that means a child will be going to school from both homes will take more cooperation - homework, school supplies, sports equipment, etc. needs to be moved from one home to the other as necessary.
My ex and I talk or text almost every day to be sure we are in sync with her schedule, activities, and her stuff. All school books and papers stay IN the backpack, which goes with her always. Karate uniform stays at Dad's house. Anything forgotten at one home is that parent's responsibility to deliver to school or the other home when needed, no complaining. Her Dad lives close to her school, so it's not a big deal to deliver stuff when needed.
I agree that as children reach middle school or high school age, they benefit from more time with their fathers. I experienced this as a stepmom to a boy and girl. They came to live with us full-time at age 14 and 16 and it was better for them at those ages. I know many single, or "almost single" moms do very well raising their children, but if there is a father involved, it can be a very good thing to have that male influence more at the older ages.
Most family courts are OK with 50/50 co-parenting arrangements, I believe. Several of my friends have arrangements like this. They deal with so many absent fathers, that a father that wants MORE involvement is usually seen as a positive. As far as the change, most children are very adaptable, and if you can be OK with a new arrangement, your son likely will be, too. At 10, though, it is not OK to ask him what he wants, this puts WAY too much pressure on him to please you both in his answer.