> Good call on the diagonal measurements but it's not a big difference in the end.

This makes a huge difference. 2x24" will give you half the total surface area of 1x48". For example, if you have 2x24" side-by-side, you could put another copy of that pair above the original pair (to get a 4x24" grid), and that would be equivalent to having a single 48" monitor.

If you cut your current X inch monitor into 4 quadrants, each quadrant is diagonally X/2 inches. So having two of those would be like having just the bottom half of your current monitor.