I posted the above temp tower as a remix on thingiverse: Bambulab X1C 0.6mm nozzle Sunlu grey PETG by WhiteHare - Thingiverse
The temp tower seems to indicate that higher temps lead to less stringing, which is the opposite of what I would have guessed…
Also, I found this thread, which appears to confirm this, and which appears to have a lot of useful information regarding stringing: Help with PETG Woes - Beard effect