I did it by paper application. As you'll see by the document checklist in the link I provided, no medical is required. I know the online application says you have to provide one, but when I called CIC and asked, the agent said no medical is required in either scenario, and thought I was crazy for asking about it.
I think there is little advantage to applying online. It gets processed a little faster, but once you've applied, either by paper application or online, you have implied status anyway, so it really doesn't matter if it takes a month or two longer to process it.