The height is related not to the number of links, but to the overall size of the foyer, as well as the ceiling height. In general though, 6.5 for a normal ceiling height, and 7-7.5 feet for a higher-than average ceiling(floor to bottom of fixture) will keep almost everyone from running into it. The actual chandelier should be 2.5-3" of height per foot of ceiling, so for your 10-ft. ceiling your chandelier itself, exclusive of chain, should be roughly 25-30". Diameter, should you be interested, is related to the size of the space; add with plus length, and it equals diameter in inches.