Hang onto that clipper setup, man. My grandpa had the same issue with his barber, guy tried a straight razor on his neck once and he looked like he got into a fight with a cat for a week. Ended up just buzzing the sides and leaving the neck line soft, no sharp edges at all. Now he swears by that old clipper guard trick where you pull the skin taut with two fingers, made a world of difference. You probably already know that though, just figured I'd toss it out there since you're dealing with that thin skin thing too.

My 1996 house had a 2-inch pipe too, same exact problem. I spent a whole summer messing with the grading before I finally measured the pipe and realized it could barely handle a heavy rain. Swapped to 4-inch like you and the difference was night and day, the water just shoots right out now.

Ask him straight up if he's ever seen a bolt stretch fail mid-flight, because that's what you're preventing. Torque-to-yield stuff is real, not a suggestion, and the manual exists because someone already figured this out the hard way. Did he actually read the section on fastener elongation, or did he just skim the torque chart and decide it was a typo? I'd make him explain the difference between a first pass seating the joint and a second pass actually clamping it, because that's the whole point. He can argue all he wants, but the book wins every time when it's your license on the line.