Exhaust sounds?

All in all the exhaust doesn't look all that bad that I cobbled together, I know that what was left of the exhaust that was on the truck will definitely need to be redone. I know that if I take it to the exhaust shop they won't use stainless pipe, what stainless I used, will probably outlast regular muffler shop grade exhaust pipe. I just don't care for the idea that to that point it is made up of 4-5 pieces of "scrap" pipe, instead of being a solid pipe from the flange to the muffler. The 1st foot or so isn't stainless, it's an original stub that came off of a super 6 manifold, but from there to about a foot in front of the muffler is 3-4 additional pieces of pipe welded together. That section isn't leaking or anything, I just want I done "nice". I could probably get by just fine letting the exhaust shop start from where I left off and finish it out from there.

But I definitely gotta replace the muffler and have them bend me a tail pipe at a minimum.
But in any case, I gotta decide which muffler to use in there. Does anyone have experience with any of the mufflers that I mentioned above and any comments on how well they like (or don't) any over another? I'm thinking about going with one of their (what I call anyways) truck and RV style mufflers, a 6 or 7" diameter round one, about 2 feet long, similar to the Walker or whatever brand is there now would the oval style be better? (Like typical turbo style-sized) or a 3 or 4" round? Those are available as glass packs or standard style muffler.
I want to go with a stainless style muffler because I plan to keep this truck around for a long time after the new engine is in. Probably not àn absolutely"have to"though I guess. My engine will have a very mild reground cam, like 1 to 1-1/2 (baby) steps over stock, solid lifters, shaved head and oversized valves, super 6 carb and stock 4 pin ecu mopar ignition.