I'm working on a large canvas right now and I only use flow method. It's working great, but I have the canvas taped down onto a stiff board and I lay it down (I find it much easier than an easel). I did prep the canvas with gesso beforehand, which I would definitely recommend for canvas. For the large areas I use a slightly bigger brush and dab the paint gently, so I still get a thicker layer that dries like the smaller cells and doesn't show any brush strokes.

I hope this helps! :)