Pro tip: started tacking tube sheets with a level check after every 4 tubes
When I first got into boiler work about 9 years back, I'd just run the whole tube sheet and hope the rollout came out even. After fighting a 60 inch mud drum in Gary, Indiana that pulled 3/16 out of square, I switched to tacking 4 tubes, checking with a level, then tacking the next 4. It takes maybe 20 extra minutes on a big sheet but I haven't had to re-roll a single joint since. Anyone else tack in stages like this, or do you just send it and trust the sequence?