I'm a little confused about the Display settings. I measured my screen and it's 50x24 1/4, so does that mean I set the display size to "1250 606.25". That doesn't sound quite right. Am I on the wrong path with this?
I'm not exactly sure what you're talking about, but FYI displays are measured in either/both their X/Y pixels (eg. 1366x768, 1972x1080) and their diagonal physical size, like 50" from bottom left corner to top right corner. Aspect ratios like 4:3 or 16:9 are derivable from the pixel dimensions, though some display modes will just not use some columns or rows of physically available pixels when an aspect ratio doesn't fit perfectly inside the pixels available.
He's talking about calculating the dots per inch to solve the microscopic fonts in KDE as described in the link above.
According to google (search for 50 inch to mm
50 inch = 1 270 millimeters
(24 1/4) inch = 615.95 millimeters
So DisplaySize 1270 616 would be correct, which is roughly what you said.