Here is my experience....i kept looking for Montreal and Toronto appointments for a month and no luck. Then i was able to find one for Ottawa, which is two hours away from Montreal, you can stay at montreal and get a bus to Ottawa or fly directly to Ottawa.

For Ottawa, i was checking the website every 10 minutes and i was able to find one after a week. Those slots get opened and get filled up right away as there are 30 thousands indians looking for an appointment as opposed to 10 - 15 nepali ...lol

Try in the morning times...i heard 7am to 10 am is a good time. I would check it every 10 minutes.

Sid