For myself I only took 8 months and then took in 1 child on a part-time basis. At that point I could make an additional $75 a week in additional income before it affected my EI. I have heard though that they changed that and you aren't allowed now to make additional income. I could be wrong. I was working though previously and didn't have a daycare beforehand. My husband was going to take a few months leave as well but we decided not to as we couldn't really afford to go through the waiting period all over again (approx. 4-6 weeks before you start getting paid). It took a few months for the family allowance and child care benefit to kick in as well.

From what I understood when I signed up for EI for self employed is that they take your net from last year's income tax and calculate your payments from that.