That would be the easy way. Only thing I'd be concerned about is if the canvas would absorb water (maybe treat it with some water-proofer) and if it would stretch. That's why I'd prefer to tie it off on pad eyes rather than snaps: You can always tighten the rope. You'll have to keep up with the canvas a little more to make sure it doesn't dry out completely and rot. But not much.
If canvas is the way you'll go, then you could take a cut piece of canvas or pattern to any shoe maker, leather working shop, or some garment shops that have heavy-duty sewing machines. Have a seam stitched on the edges so the canvas doesn't fray. The leather working shops could even put in the snaps or metal thru-holes for you.
A more expensive way to go would also contact a sail maker. But that cost would get up there.
If canvas is the way you'll go, then you could take a cut piece of canvas or pattern to any shoe maker, leather working shop, or some garment shops that have heavy-duty sewing machines. Have a seam stitched on the edges so the canvas doesn't fray. The leather working shops could even put in the snaps or metal thru-holes for you.
A more expensive way to go would also contact a sail maker. But that cost would get up there.