I measure the bore with mics and hole gages. If not in alignment, the cam will bind. Like I said above, your technique is a throw back to the Model T era, when bearings were cast in place and had to be line bored to size and alignment. As old as our TR’s are, they fall into the more “modern” manufacturing era, when bearings are precision cast using layers of different soft metals within steel shells and sized to 1/10,000,000 of an inch. Unless the block was bored wrong during initial manufacture, mis-alignment of the cam bores is just not a problem. If it were, the cams would have failed, like 50 years ago, showing the flaw long ago.
I am not at all criticizing your meticulousness. After all, your technique of bearing repair was used to keep thousands of Model T’s on the road for over a million miles each! Here in the states it’s pretty much a lost art, though. I live in a city where, Boeing, Lockheed, Bell, and several other companies produce aviation products. I am blessed with being driving distance to many very cool, state of the art, metal processing companies...and I would be hard pressed to find a company willing to cast and bore bearings inside a 60 year old block!