I used the exact Quickrete form to make a patio next to the house. 112 80 pound bags later it's done! I'm sure you know that 1 80 pound fills the 2x2 form. Long story why I did this instead of a pour or asphalt. Anyway, here are some of my thoughts in no particular order.
Of course base is important. I had pretty level hard packed dirt. I just leveled the form on the dirt by placing various size stones under the form to reach level. Be careful the form doesn't move when dumping the crete in. Uneven base I leveled with sand. 1 bag fills the form with some leftover. Leftover is engineered in to fill an eneven base. I live in PA. I was worried about freeze/thaw heaving them. I did this last year and over 1 winter no problems yet. When you lift the form up some stones will get pulled up at the edges, no biggie use your finger and gently form them back in place. I mixed the first couple bags by hand. Due to my large job I bought a HF mixer. Ran that sucker hard but worked fine and sure saved my back. I did not put anything in the joints as I blow off and pressure wash the patio and would just wash out sand. My
thought is that motar would crack out also. I did not use any colorant. I just use some weed killer between the joints and I'm happy with that. Sorry I have no digital camera, I'd love to show off my job.
Any other questions just ask, I have a bit of experiance with this. I'm only here on weekdays though
Best of luck!