We applied a month after my wife had 1095 days. I myself had been in Canada for 6 years then. We could have applied earlier had it not for other priorities that kept me busy by the time we were ready to start with our application. Maybe a week buffer would be enough i think,as long as you are really sure with the your calculation. Now with regards to additional documents, such as health records....etc, we did not bother to acquire and sent in. Our kid was 4year old then(under school age),born outside of Canada. My wife and kid rarely seek medical attention, maybe once for my wife and twice for our child, so medical record wasn't that reliable to suffice her presence. So if I were you, I will not worry much about sending in additional docs. If they ask afterwards, then you send it. CIC would have had specified these documents in the checklist, if they really need these for your application. But at the end of the day, it is still up to you.