i need to do an estimate for building a small retaining wall. it's going to be 180' long, following a scalloped flower bed. they want to use those trapezoid shaped cement blocks. it's supposed to be two blocks high, and then backfilled with dirt. the flower bed is roughly 1.5 x 180 feet. the blocks will go on top of a cement slab. the flower bed is approx 2 inches lower the the cement slab. what should a job like this run for a two man crew? i've never done anything like this before so i'm completely in the dark.