Nah, it'll take more than that to exhaust this thread, Flip.
So, current state of play is that I have re-lacquered the carbon sleeve and knocked the inlet endcap back into shape, removing a few dents as best I could.
I then offered the sleeve back up to the innards, only to discover that the inner perforated tube has taken a knock and was not concentric, meaning that the can didn't want to go back together nicely.
A bit more tippy tappy with an ally-faced hammer and a further trim of one end of the sleeve has it trued up close enough as makes no difference and the endcaps now fit on neatly.
I was polishing the endcaps but had to come in from the shed after just one was done cos my polisher is ancient and gets a bit hot if you run it for too long.
Flip, the innards of your old can were way better than this one was.
Shame I can't do pics but the charred remains of the old wadding was only 12cm long and the rest of the can was merely an open echo chamber.
On the plus side, the perforated tube was lined with stainless gauze and this was still in good nick.
I've been pondering the rivets all day and I must admit that I'm erring towards a preference to fit ally ones.
As Dukedesmo suggests, I reckon its a better bet for a carbon sleeve and also should make later dismantling for repacking a lot easier.
I'm a bit worried that the carbon sleeve wont like the crushing force necessary to fit stainless rivets.
And anyway, ally rivets were fitted originally so it makes sense to stick with that.
Sourcing some suitable blind ally rivets might not be so easy though. I've not found a supplier yet.
Thanks loads for your inputs, everyone.
It makes a huge difference, not only to the quality of the end result but also to the enjoyment of the process in being able to chat about it as I go along.