Unless you flat-mount your canvas, you need from 2-3 inches for stretching canvas. That means on a 24 inch printer, you have an effective maximum width of perhaps 18-20 inches by whatever length you choose. Canvas seems to beg for big prints, so a 44 inch printer one can print up to about 38-40 inches by say 60 inches. 36 inch canvas allows up to about 30 inches wide, thus easy to produce a 30x40 or 30x50 print. Since there are few, if any 36 inch prints (that would almost be a sweet spot for a larger-fomat printer;-),
You sort of need to think like a chess player, many steps ahead and a camera or two. For me, I can easily print 10-12 MB captures up to 30x45. With my 36 MP camera, large is even easier and the image quality even better.
A 24 inch printer is nicely-sized for a smaller studio and there's nothing wrong with 20x30–24x36 prints. That's usually the maximum I do for 95% of my printing. However, with the 44 inch printers, they've allowed me to print larger for both maximum impact and to print many, many nice canvas images that, once stretched, need no framing. Coating and stretching is another issue you'll need to consider, along with having several friends with strong backs to help you drag your printer though your door and setting the thing up.
Paper storage is another thing to consider. You'll need more height or depth to store the rolls. 24 inch rolls fit in my custom cabinets, but longer, stays in the corner and under the table stacked. A cutter is another tool that comes in handy with these printers. I bought a 36 inch Rotatrim after getting my 24. I don't have room for a longer cutter, so wider than 36 inch stock gets cut on the floor with a straight edge.
A 24 inch printer can easily be moved by two people and takes up a little move than half the space of the 44 inters.
At times, I wish I had the 60 inch printer, but don't have the room. When I need it larger, I've got a couple of places who can do both paper and canvas and in ten years with my stable, only had one job that needed that size. Besides, 44 inch canvas/paper is already a chore to handle and load.