How should I attach a cat back exhaust?

Looking for advice... there are tons of threads here on which cat back exhaust is best, but I haven't seen much on the best way to attach the new exhaust to the pipe from the cat. I plan to delete the resonator. Is it best to just line them up dry and tighten the bolts down? Should I put in an exhaust gasket or use Copper RTV on the joint? Should I use red Loctite on the bolts? Finally, how much should I tighten the bolts? I want to avoid any leaks at that joint and I sure don't want the bolts to come out. Also want to make sure they can be removed if I ever want to switch back to the stock exhaust for resale, etc. Thanks.

I dry fitted everything, used rtv in the connections, tightened the bolts down as tight as I could, and then had a shop spot weld them in place.

I'm thinking that it depends upon what you're attaching it to.

I have MagnaFlow cat back pipes, and wanted to have it so the system could be removed if needed. But with the bolts tightened as much as possible, it leaked so bad I had to have a shop weld it all into one piece. She's permanent now!

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Got it all installed yesterday with the Dirty Deeds system, and my concerns were totally overblown. It connected where the stock resonator would be attached, and the Dirty Deeds flange fit perfectly. It's tapered for a perfect seal. No need for RTV or a gasket. I was also careful to tighten it progressively, alternating sides and doing it bit by bit.