I remember fighting a 3/8 inch line set in a crawlspace back in 2017, barely enough room to roll over, and the flame kept blowing right into my face because of the airflow under the house. Finally gave up on the torch and used a mini butane one, which worked way better for the vertical joint. But then my helper dropped the coil and we had to start over, so I don't know if I actually learned anything about technique or just got lucky. You ever have one of those jobs where the fix is dumber than the original mistake?