suggested keyer weight for amp tuning
 

Hello, I have a little used MFJ-492 electronic keyer that I've decided to
put to good use as an amplifier tuner. (This is my first amp). The keyer
defaults to a 50% duty cycle and I would like to get this down to around 10
or 20 percent. Any suggestions on what weight to use? This keyer is
adjustable from 5 to 95 percent weight...I do not have a scope so would have
to guess by ear. Thanks for the help.
Craig KB8FGC