for determining custodial parents you count nights, not months, the child spent with each parent. it's the one that the child lived the most nights that is the custodial parent. REG 1.152-4(c). that would seem to be you.
about 150 nights with you the first 5 months plus about 147 nights for the last 7 about 300 total
which is greater than dad's of about 150 nights the first 5 months and about 63 nights for the last 7 about 210
