If anything, at that stance, putting on larger wheels will make the arch look like it's less filled. One thing that creates the illusion that the arch is not filled is the sidewall height of the tires. Since you will be keeping the stock diameter when you put on larger wheels, the sidewall height of the tire decreases. Therefore, if you could fit 24's under there, you would put on a tire with a narrower profile. The end result makes the arch 'look' less filled. Once you lower it though, that problem tends to disappear.