Plug chop

OK so time for the plug chop. My bike runs good at all ranges except WOT now. I would like to find out if lean or rich. Question is how can I do a plug chop if it doesn’t hold consistent power at WOT, or do I not need to? All the instructions on the web talk about holding it at WOT but this feels dangerous given it’s running condition

Cheers

Plug chop