For 4 inch tiers with ribbon on the bottom edge, would a 5/8 ribbon be wide enough? There will be piping on the rest of the tier. My bride already has that width, I didn't want to worry about getting another size if I didn't have to.
It will either look really sophisticated or will be so small as to be unnoticeable. Is there any way you could try it up against a 4"-high dummy to see what it looks like?