Wouldn't it make sense to pick up a small mixer to save time? Toss in a bag of portland, sand, water and your guys can be laying in a minute with fresh shoulders, not worn out from mixing.
2004 Chevy 3500 Dually 4x4 CC/LB D-Max/Allison
Western 8'6" MVP+ w/ wings
Western Pro-Flo 2 Salter