Walker ball-style/flared collector coupling on Magnum manifold - flange problem?

Here's the story:

I picked up a pair of these Walker universal ball-style collectors to mate with my 1992/93 style Magnum exhaust manifolds:


(FYI, these are the 2.5" versions and won't work if you're trying to cross-reference part numbers. You need the 2.25" version, P/N #41725 for the large-flange Magnum manifolds.

They fit great, but I have a slight concern. Unlike the OEM units, the flanges are (obviously) flat. There's no chamfer on them that would allow the flange to seat around the flared end regardless of whether the pipe sits parallel with the manifold outlet or not.

Unsurprisingly, I can't fit these things without angling the pipe relative to the manifold. Regardless of what this looks like below, the manifold outlet is definitely not in line with the pipe in this picture:



This brings me to my main concern:
Can I rely on those flat flanges to seal the ball end, even if the pipes are not parallel to the manifold? Or should I get a pair of chamfered 2.25" flanges (like the one below) and replace the flat flanges?


In my mind, it would seem as if the flat flanges wouldn't be able to spread the clamping force evenly against the ball end, and may result in an exhaust leak.

-Kurt