Nat'l Wood Flooring Ass'n Recommends trowel glue in addition to nails on anything wider than 4". definitely follow previous comments also. If you live in a drier climate, floor will gap more than buckle. humid areas look for "humps" and buckles. You'd do well to select a stable species also. If a sand on site floor, give a few days between install and sand.
Good Luck!
William
Heritage Hardwood Floors
Coeur 'd Alene, ID
P.S. No paper needed if you decide to full trowel glue. I know that sounds obvious but you'd be suprised ....
P.P.S Hand scraped (even DIY hand scraped) looks great in wider planks if you're into that look. e-mail at
jclivzinme@msn.com if you want advice on how to hand scrape planks yourself