I just strapped my new Magneto V2 onto a friends suppressed rifle this weekend. He's got a SAC 308 with a ~22" barrel and a TBAC 30P1.
We pulled the cover off the 30P1, and strapped the V2 on there. Didn't need to finagle anything in terms of the shimstack to get the bayonet spaced properly.
I didn't want to take any chances of melting my V2 though, so I think we only got 3 or 4 shots off before taking the V2 off to allow the can to cool for a few minutes.
Because the can cover is kind of lumpy/bumpy/amorphous, I was concerned strapping the V2 on top of the cover wouldn't work, or be stable enough....
Bottom line: Attaching the V2 directly onto the can works fine, just don't melt your chrono.