I will go to the stories and talk to the managers or find some of the warehouse factories and talk to them. Both places don't want to use any of them if they are bent so those are the ones I use.
I agree you can use the 2x2 but it just is something else to buy. I have also used house windows and just framed them in as well. I get those at the salvage warehouse placed for $25 or so.
-------------------- Big ones line-up, little ones bunch-up