Legal Question in Family Law in Illinois

Zero. First, Illinois does not do split physical custody (see earlier posts). Here is the reason:

The courts do not like to confuse a kid and not have one stable environment where he can call 'home'. It wouldn't work once he is in school anyway, so your asking for a temporary solution. The courts like to establish stability and upending a child's entire living arrangement in a couple of years is not stable.

You have to think whats in the best interest of the child. Honestly, your request is probably more for your benefit then his. While many non-custodial parents wish to have more time with their child (and some simply wish to avoid paying support), the reality is that the living arrangement a good parent should want for their child is the one in which the child is most likely to become a well adjusted, happy, kid who is successful in school.