I have a pre-cut 10X12 pergola arriving soon and I am pouring the footings for it next week. The wife really likes the look of this pergola. So, since I live in New York I will be using four 12" round Sonotubes 4 feet down for the footings. Question is: How do I square it off for the brick veneer above ground level??? Should I cut some plywood up into 2x3 foot sections and brace/screw together from the ground level up and pour mortor?