SNS3Guppy, that's total bo**ocks, it makes you come across as a troll whose only knowledge has come from textbooks! I presume that's not the case, so please go out and fly a carburetted Lycoming or Continental that's fitted with a multi-cylinder engine analyser and try to get all cylinders LOP without using the above techniques. Chances are you won't.
Reading comprehension was never your long suit, clearly enough.
From my perspective as a pilot, mechanic, and instructor with ample experience operating, maintaining, servicing, building, rebuilding, and caring for powerplants...you might need to get out a little more and fly.
I've operated recip engines lean of peak from small displacement engines to large radials...each with carburetors, sometimes fully outfitted with individual cylinder instrumentation, sometimes not. And yes, it really can be done. Just not by you, it would seem. By thousands of others...yes. But not by you. And that's okay...because nobody is forcing you to operate that way, and you don't need to do so.
That's really not relevant to the discussion, however, nor to the turn taken in the thread by Mr. or Mrs barrow....however misguided his or her insight may be.