Depending on what amount you plan to mix up. Your answer is correct if all you want are a few buckets full. If however you want several cubic feet in a short period this helps by allowing big bags of mix to be done at once.
About 36 by 24 inches, a great size.
I really do not understand your question. Are you asking about how much concrete can be mixed? I bought my unit to use to hold water under a fountain on a patio. It is perfect for that.
Most definitely! That's what I use mine for.
Two sizes. Specs on website.
Generally, food grade items state "BPA free" or "uPVC" or Rigid PVC... None of these are listed so I'm inclined to think this is not a food safe plastic and meant for non-food projects.
for $13 you can buy a new one. My time is worth more than that.
This tub is good for small jobs just as long as you do not use the sides of it for leverage while mixing. The colder it gets the easier it is to split the sides.
It's 4' x 2' x 8"
Specs on HD website.