pickup bed wood

[larry harding]

1...a friend who is in the sawmill and wood business got me some pretty walnut to do the bed floor and side rails. before doing the final planing, what is the proper thickness for the bed wood? i'm cleaning up at 7/8", but can easily go to 3/4" if that is the correct thickness.
2...what would you guys do to finish the wood, linseed oil, tongue oil, or some clear finish like polyurethane. i fear that a clear finish would be vulnerable to chips as things get banged around.