Thread: Minimum shoulder for a suppressor?

On a recent thread there was a bit of debate over thread sizes and whether or not opening up of the muzzle occurs.

Without going back over that part of the debate can I ask what everyone feels is a good minimum shoulder.

I've just been looking at suppressing a .308 and at the point I intend to shorten it to the barrel measures 16.5mm. I'm thinking a 14 x 1 thread will give me heaps and am wondering whether to go larger (just in case opening up does occur). I'm guessing the 14 is the outside diameter, by that reckoning then a 15 x 1 would give .75mm(.030") of shoulder? Is that enough or should I just stick to the .050 shoulder that 14 x 1 would give?

So aside from answering my question what do people consider the minimum shoulder that one needs?