If you have access to a drag strip, I think that jetting to the best MPH is easier for most of us to set the WOT mix.

Just make enough back to back runs to establish a solid MPH base for comparison. Then jet up until the MPH starts to drop off, then step back to the optimum.

If at that point you want to start consulting the plugs, then okay.

It is much quicker to change main jets than to pull a spark plug on a hot BBM. And you do not have to learn the intricacies of reading the spark plugs, unless you want to.

I am not saying that this will result in a perfect A/F ratio. But it will get a good reliable result with a reasonable amount of effort and knowledge.