One of my grandfather's favorite sayings was:

"Every job is easy if you have the right Tools"

to really do what you want to do
you need
EGT,
wide band oxygen sensor
at minimum
and in the ideal case.....
a set of eight spark plugs with fast reading pressure sensors embedded in them

Before using stock cast Magnum heads on a high compression and lean air-fuel engine set-up I would "temper" them in an non-oxidizing atmosphere oven at 520 degrees F for 24 hours, and then polish over the sharp edges in the combustion chamber.