ACE, seen the brass nut comment a couple of times, why brass?
Because the brass nuts won't rust on to the studs, and they always come off nicely when you need to take them off.
We started using brass nuts at the British car shop where I worked in 1973, because we were always fighting with rusted and seized exhaust hardware which also often caused broken studs in the heads and exhaust manifolds. On all our exhaust jobs, we began using brass nuts, and when these cars came back in for some job that required exhaust removal again, the nuts came right off. No need for soaking in penetrating oil, or heating them up with a torch, or busting them off.
They worked out great.
BTW, the guy who owned that shop rode a RE Interceptor 750.