if 68130 is a zip code, that is in NE. they will likely have much fewer problems with Blue spruce than we do in the midwest because of lower RH during the early and late growing season. I do tell a lot of clients "don't plant blue spruce...I really should tell you that blue spruce is a great idea because I make a lot of money treating them. But if you want a healthy tree, don't plant Blue spruce".
to the OP's question: 8-10..maybe 12'' are typically largest trees available. There are most certainly bigger ones out there, but I don't see them often. That will probably be a a 2000+ LB rootball.