Well Jerry, being an old fart, I do it the old fart way.  My voltage
controled oscillator goes across the watt meter, and I peak the pitch for
output and minimize it for minimum SWR.  Tune for highestt pitch for
highest output.
A friend built me a refference oscellator for the Valiant, and that idea
would work if you had to dip the plate, but most amps are either no tune,
or peak output at least for SSB usage.
I haven't seen any system that is responsive as the old way.
Note the Valiant, I have a TR4, a c-line, an sx71 and an hq180.  So maybe I
am not the person to listen to.