I need some help on a bid for a retaining wall. The wall will require minimal removal of the bank, probably 3 hours and i have to install a wall that is 16 inches tall 100 feet long. It will require laying 400 blocks. I need an idea on what you guys would charge per hour, per block or per linear foot. the blocks I am using are 12 inches across the face and 4 inches tall. I don't want to take a hit on this and want to be competitive w/ others in the area.