Welding set up is a Hobart 140. Think I am using an 80/20 argon mix. I am not sure how it will react with the ss wire as I have read conflicting reports on the gas to use. As for flex at the top, the two we did yesterday are just ground smooth with a mild bevel. They had very minimal flex but could if you applied force. Mine I hand rolled the lip over so it is strong as ever. Unfortunately I wasn't thinking an rolled it inward. So I hit it with bleach water a day or so before brew day to kill anything that may be in it. I plan on cutting the lip off and re-rolling it outward. As mentioned when I get on my computer this am I'll post pics of mine. The one guy was real excited as he does BIAB and said the old normal opening was a real pain in the arse.