I respectfully disagree with StevieJ. Developing and using your little finger is a good idea. I tend to follow Paddy O'Brien's advice to use primarily your index, middle, and ring fingers in the lower octave, and your middle, ring, and little fingers in the upper.
It seems there are really two distinct schools of thought on this issue - with a grey area in between no doubt. Rob has been playing boxes of different stripes for far longer than I have, and so normally I would be inclined to defer to his experience - were it not for the way I heard the advice and the effect it had on my own playing. So Maze, I think it's something you should keep an open mind on, experiment with and do whatever works best for you. (You are still reading, aren't you?)
My natural inclination on taking up the box was to try to make as much use of the little finger as possible. After I had been playing for a year I got 5 minutes of advice from a very fine C#/D player, Noel Scott. He really stressed not using the pinky at all, basically, and developing the ability to scoot up and down the keyboard using either just two or three fingers.
It seemed totally counterintuitive, but Noel being such a great player, I decided to give it a trial for a few weeks and set about relearning all my tunes without the little finger. The effect was instantaneous. I can't say my box playing took off, because it's still nothing to write home about, but almost. Mobility and confidence improved immediately and tricky passages involving the 4th finger miraculously became easy.
I'm curious to watch other players more carefully but I don't encounter many. I did stare at Jacky Daly's right hand for a week in the Catskills last year and I can tell you he very rarely uses the little finger. In fact a week's worth of tunes that he taught us, he pointed out one place where he thought it was a good idea to use the little finger - for a B-b-B jump - and apart from that I don't think I saw him use it at all (not counting graces).
I wonder if the pinky is more useful for B/C players because of the more frequent cross-rowing. But then Noel Scott played B/C for about 20 years before switching to C#/D a few years ago. And Ena O Brien, a well-known B/C player in Canada, does not use the 4th finger herself (though she apparently tells others they should!).
Make of all this what you will. My experience is limited after all.
Question for you, Rob: when you say 'cut' with reference to P O'B's rolls, do you mean a higher note or the semitone-lower note on the outer row?
PS Just noticed Rob's edit about omelettes.
Absolutely right - but nothing says you shouldn't watch good cooks making them and try things out for yourself.