Used to eyeball my tube rolling by sound, now I use a Sharpie mark and feel like a pro
First shop I worked at in Gary, the old timers told me to just listen for the pitch change when rolling tubes, and I did that for 3 years like an idiot. Bought a $12 paint marker after a leak test failed on a boiler at the BP refinery and now I mark every tube at the seat before I roll it. Anyone else pick up a cheap habit late that nobody ever taught you in your apprenticeship?
Did you ever go back and check how far off your ear was on those first ones? I did the same thing for years until a buddy showed me how the mark lets you see if the tube walks out while you're rolling, which the sound alone won't tell you. Twelve bucks for a marker that saves you a re-roll on a bad seat is about the cheapest lesson you'll ever get.