Tire width is tire width, regardless of diameter. What do change are diameter and volume. A 700x28 tire is a radius of 343mm and volume 1.25L, 700x44 is 359mm and 3.2L, 650x47 is 359mm and 3.4L, 650x50 is 346mm and 3.9L.
There’s no difference in a 47mm (actual measured width) in either diameter. However, a tire labeled as a certain width is based on an assumed rim width. If you use wider rooms than whatever they assumed, then the tire will actually be wider. Also, tires stretch a bit over time which varies by construction. Then there’s also the fact that the tires aren’t always the width the manufacturer intended them to be. Long story short, check your actual tires on your actual rims and check again after a few hundred miles. None of those factors are dictated by rim diameter.
The other thing is how much clearance do you need around the tire? ISO spec says there should be 6mm on all sides (left, right, top) to the frame to account for rocks and mud. A rock can jam in there and give you a bad day. Mud can build on your tires and act like a belt sander, cutting through your frame (even aluminum!).
I’m comfortable with 4mm on each side. Some people go lower. ISO declares 6 to be safe. Take your pick.