I'm big into Fours right now and I have a pair of both O-Matter and Mags. I thought I'd do a little experiment to see if the lenses could be swapped. Logic says they're interchangeable right? Wrong! The O-Matter Four lens oddly enough is cut differently and won't fit the Mag Four and vice versa. So now I'm back to the same place I've been for a while now; I need to know what the base curve of the O-Matter Four and the Mag Four are so that I can custom cut my own lenses to fit both frames. I know absolutely that they aren't an 8.75 like Flak Jackets, etc. are and it doesn't appear that they're a 6 either provided that the Garage Rock is that base curve. Can someone help? I need to find the right donor lens to do this!