Lug Nut Size

Errrgg, been searching for quite a while now and have not come to a definite answer as to what lug nuts I need for these new rims I just picked up... The wheels are the Moto Metal 951s and they did not come with any lug nuts. I plan on putting them on a 2003 F350 SRW and I have heard that I cannot use the factory lugs. The most common answer I am finding is that I need 14x1.5 Bulge Acorn style (?). Does the hex size matter? Length? Any thoughts would be extremely helpful.