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[alrightythen]

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[ohmelody]

Hi there,
My recommendation is to let your professor know as early as possible! That way, they'd be able to meet your deadline without any hassle. When I had first applied, I made the mistake of notifying my referee only two weeks in advance and let's just say the situation was less than ideal lol. 
From what I know, schools in Alberta have a similar deadline as OMSAS so when making your requests, referees can submit their letters around the same time for those. 

[shakeshake]

This is a bit out of your control. I would make sure to tell him the timeline of things and then send him a reminder when the portal opens, but do not be surprised if they submit/write your letter closer to the deadline. I wouldn't hound or put too much pressure on them to submit right away either as like you said they are busy. The reality is most university professors have written letters before and likely have a template they use which they then add examples/details to. Provide them with a CV and briefly summarize in your email to them with reference instructions what you felt the highlights of your experience was with them. Make sure they understand they have to write the letter AND submit the CAF (not just one or the other). 

 

Good luck!