OK, you say you are religious about your stuff, but you also say you never had to adjust a 2-stroke carb. There's a disconnect there. All 2-strokes take tuning for field conditions. High humidity hot day is one thing. 60* at 11,000 feet is another. Cool dry winter day is another. They need attention. That's why the jet screws are there. If they didn't, they'd have fixed jets.
Always run 2T or EGD rated oils - or better. 40:1 or wetter. The book ratios are for the US EPA, not the sawyer. There is no protection between the metal moving at XX,000 RPMs except the oil.
NEVER run lean. Wet, the worst you'll get is a fouled plug and some carbon. Lean and you'll be buying a motor.
If you want to try an experiment, take your buggered but running saw out and start cutting with fresh gas/oil. Regular gas and good oil. Open the high speed jet as you cut (between short cuts) until it starts to 4-stroke in the cut. Back it in 1/8 turn and see how far you were from their shop tune. I'll bet you are more than a 1/2 turn lean. If so, they are not your tuners of choice
Be ready to do this any day that is not like your average saw day. This is your basic field tune. Once you have this down pat, you can work on clean idle and good pick-up from idle. Once you have all that figured, you are ready to go anywhere and cut anytime with any saw.
Your old Craftsman was tuned right, or at least on the fat side, and it lasted. These will too. You don't need new saws, you need to rebuild these and tune them right. They are good saws. Once you and they "become one" and get in sync, you'll be cuttin just fine