Heck, Jim, that's kinda like asking how closely matched a woman's breasts need to be. If it's a pair that gives you pleasure, then I think it's a good match. I used to think this forum was kind of like a car forum, i.e., what mod will give me the fastest 1/4 mile. But I have come to realize it's kind of like a wine forum, or maybe a wristwatch forum. So many of the choices are a taste thing.
So I'm sitting in the listening room this afternoon, spinning a nice minty mono pressing of Jimmy Smith's Organ Grinder Swing. From the sweet spot the image is dead center. From the rear seat it seems to pull right. PB comes up to the room and I ask him to sit in the rear seat and tell me where the image is. He finds it dead center. Who's right!?!?! Like fingerprints, everyone's ears are a little different, and things like tube matching are pretty tough to generalize. FWIW part of the reason we use a C4S is that it helps to make tube tube try to hit the maximum mu specified in the manual.
Hopefully folks who want to tweak the amp to the last degree will find the price of 6c45pis reasonable. I haven't owned more than a few pair myself, but they never failed to impress.
