Unfortunately, the spell specifies that you need to be within 5' to actually read the runes. It doesn't matter how good your eyes or how big the runes are; if you ain't within five, they're illegible.
Do you have a cite for that? What I read only (really really strongly) implies that you have to be within five feet to read the runes. Sure, it makes sense; but I think it is a slightly gray area.