Yes - I would try to find quality childcare so that you don't feel dependent on him for childcare. You want him to be a parent, not a babysitter. And think of yourself too - do you want to be a full time teacher/homeschooler and spend your weekends working, while x gets to play and do all the fun weekend stuff? If you have a right of first refusal and share weekend custody, then he could still possibly have the kids on the weekends if he likes while you work (but I would never have it written as an access schedule order).
I'd really try to ensure you get your fair share of weekends. I just recently met a mom who is primary residence midweek parent....but her x has the kids EVERY weekend. Her kids are in school all day. I would hate that - moms can be just as fun and should have every right to have that role too. And the kids deserve to have their time off school shared equally too...so they can go away camping with mom sometimes too! (or whatever is fun weekend stuff...)