Re-grinding a cam, educate me please

OK, not sure why you are asking us, why not call Oregon Cam. The way they really regrind a camshaft is first you pick a lobe that will fit with the material left on your used cam lobes. You can only "adjust" your angles, lobe separation, so far since you need to hit solid metal when you grind the new lobes. They regrind the new lobe with a smaller base circle to get the lift and duration desired. Again, you can only go so far, since you need metal to make the new lobe. Since the base circle is smaller, you may need different length pushrods. This is a simplification of what they really do. You can weld lobes to get most profiles, but I imagine that gets costly quick.