I talked to Bobby in great length about the canister set up. He said the mount on the canister is critical. If it's too firm the header will break. I made up a support from plywood/tubing, but just wasn't satisfied with it. Seemed a bit too rigid for me, so I used the mount that CA offers.
I have similar set up with my canister, like your pic.
After talking with the welder, we conclude to not install the clamp on the teflon coupler. This would give a little play (1/4'') between the header and canister inside the teflon coupler for header expension.