If this is just for the "high guys" I'm not one of them, quit doing that quite a while ago. If it's for anyone, 2x2's would not be my first choice. I would assume this is just a partition wall and would not be load bearing. A wall would generally have 3 plates, 1 bottom and 2 top plates. If the height of your walls is standard, 8', 9' 10', I would purchase some pre-cut 2x4 studs, if not you would need to cut each stud. Nail the wall together laying on the floor (the wall laying on the floor not you), then stand the wall up. You may need to get creative with the top plate, a 3/4" board and 1/2 " plywood or something. It will depend on what your ceiling is finished with. The other consideration will be which way the wall runs, the same way as your rafters or the opposite way. If it is the same way and the wall is between rafters you may need to put some blocking between the rafters to hold the top of the wall.
There are other considerations, such as if this is a concrete floor you may want to cosider treated bottom plates.....