We know general instructions for chosing a tip, setting pressures,
lighting the torch and setting the Acetylene so that the flame is just
about to leave the tip. Then we add O2 until we get a flame with just
a little feather. Written instruction seems to stop there.

However, we know one can adjust the torch for a larger or smaller
neutral flame, so each tip has a range of useful flame sizes.
At the low end the torch makes no noise; one opens the torch and you
go thru a hissing sound, to the roar of a jet engine.

No one seems to discuss how to determine the upper end of this range.

Can someone discuss how to determine the upper range of a given tip
size? - Mike