Remember that as the diameter goes up a little, the volume goes up a lot.
For example: 7" wheel that is 4 inches high holds 153 cubic inches. An 8 inch wheel that is 4 inches high is 200 cubic inches. That's a 33% increase with one inch. That means 33% more milk. A 8"x14" tall wheel would need almost 5 times as much milk as a 7"x4" wheel.
The reason I mention this is because I made this mistake myself early on and had a 12 inch stainless steel hoop made! I just thought I'd use a little more milk and fill it up. I now make 20-24 gallon batches of cheddar and still can't use it. The wheel would just be too thin. I did use it successfully this week for the first time in 8 years of having it because I made a gouda which I guess has a lot more moisture content. It wound up being about 4-5 inches high after brining. i am looking for a 10" piece of pipe myself because that seems to be about the right size for my gouda batches.
You sound like you are after the same thing I am. It takes just as much time to make a 24 gallon batch as it does a 1 gallon batch. Why not do it, right?