Exhaust Clamp Size?

I'm doing some work on SuperTrapps soon (repacking), and I've decided to replace the clamps while I have the 2-1 collectors off the headers. The clamps are odd to start with, and one is missing, replaced with a standard worm-style clamp. I was going to replace with stainless t-bolt clamps (like which hold the cans to the mid-pipe). So I went out and measured the OD of the pipes (as best as I can with everything on the bike).

Roughly 1.65"/42mm.

Which is right on the edge of the adjustment range for the various t-bolt clamps.

So I'm going to give these a try: http://www.summitracing.com/parts/sme-240175

Anyone have any recommendations for clamps to use (or size clamps to go hunt down), other than these?

Now, I seem to remember there supposedly being a gasket in there as well (per the service manual), which I'm not sure if I've actually seen when having these off in the past. Just copper RTV and call it good between the pipes?

My goal in all of this is to make the bike sound better, closing off any leaks, replacing the packing, etc.