how much knock is to much??
As for KR, you want none.
past peak torque by several degrees at least. Though
you have to distinguish between knock that is just hanging
on, from some previous "event" (like throttle mash, air
before fuel catches up), knock that happens because the
horsepower gods hate you (bad sensors, valvetrain noise,
exhaust banging) and knock that is showing you a steady-
state misfueling or overadvance. Starting from none is good.
If you're any kind of close to best timing then minor changes
will yield you nothing. Fuel probably matters more; that's
factory-whack at WOT. I'd leave spark for last because any
fuel messing will definitely change what the motor wants and
what it will tolerate (ping / KR telling you only the latter).

