I can use my 24mm with the .58 finder if I need or want to. I do not rely on the finder to show where the frame edges are, because it doesn't. But I can use the camera finder to line up my verticals and horizontals and basically compose the shot the way I want it. Then I rely on my judgment, my sense of the actual coverage of the 24mm lens.
That said, I use an auxiliary finder with the 24, most of the time. have the Zeiss 25/28; the Leitz 24; and the CV 25, and I find them all pretty satisfactory.
I agree that the Camera's finder does not give a good sense of the perspective of a lens this wide. But I would not say that the auxiliary finders are all that much better in that regard. Some have some distortions of their own that are a bit different from those of the lenses. The Zeiss is probably the most distortion-free. I think the best way to see what the lens sees is to use an SLR with lenses that wide; but then you don't get the same kind of image quality. There's no perfect solution, I guess.
