I bought a really nice torch setup from a friend about 20 years ago, and haven't used it yet. Propane torches are so handy and effective.
As far as the female pipe, I'd weld it. My Caddy exhaust that I gave away a few weeks back had originally been clamped together. It was really loud, rattled, and didn't fit good. I took it to a different muffler shop and they tweaked the bends and fully welded it. Immediately it was considerably quieter.
I'm a fan of fully welding, and if you foresee the need to separate it in the future, put in a flange.
As far as the female pipe, I'd weld it. My Caddy exhaust that I gave away a few weeks back had originally been clamped together. It was really loud, rattled, and didn't fit good. I took it to a different muffler shop and they tweaked the bends and fully welded it. Immediately it was considerably quieter.
I'm a fan of fully welding, and if you foresee the need to separate it in the future, put in a flange.