None of that matters. If you add a curve to a cue shaft or butt it will have to get smaller in ID than it was previously upstream. This is fine if the smaller section falls at the end of the butt but anywhere else and you have yourself a funky odd looking POS with a lump in it.
Nothing complex about that. It's 2D conception, not the frigging universe big bang. You may fancy yourself a mathematician but this is not calculus.
You are vastly misunderstanding how curves work, and are massively misunderstanding how important calculus is to the understanding of this subject. Your perspective as to where the curve is, is the problem. And it’s not a hump. It’s the peak of the curve, and it’s relation to the start and end of it. Think of a sine wave that transitions to an exponential curve. That’s an extreme level, but draw it out long enough and due to the offset of the taper. It creates a ‘hump’ when rolled. But it’s due to how the curve isn’t parallel to a centerline.