Cool, the projected cost cost is a little lower than I thought it would be.
I think I would need 10 96" 2x2 for this project.

The measurements I came up with for a 4 tub rack instead of 6 tubs is:
4 x 44"
8 x 27"
12 x 24"
8 x 21.5"
4 x 10" (scrap for spacing) pieces of 2x2.

Does that sound about right?