I made a planter that was 4x6 ft, five blocks high, and the blocs worked well. I lined it with landscaping cloth to keep the soil in. Its about 6 yrs old, still full of soil!
To better have your question answered, please call Pavestone at 866-409-7971.
The thickness of the stone is 3-3/8 inches.
The Home Depot page for the "RumbleStone Medium 3.5 in. x 7 in. x 7 in. Cafe Concrete Garden Wall Block" lists a pallet as containing 144 pieces.