From such a detailed description I still don’t really understand what you mean. Is this correct? You’re producing a cylindrical core using different sizes of sheets and stacking them to form the cylinder. Then you decided you’d go for uniform sized sheets instead. Personally, I don’t think you have much of a problem. The only requirement I can say is that the area of the core needs to be the same. Plus, of course, the quality of the construction needs to be just as good.