Sorry for your frustrating time. I have followed your thread and probaly understand what you are going through more than most, 2-cycle engines have been part of my professional and recreational life for 50 years or so. Point ignitions are a simple mechanical device, however they are subject to wear and require regular maintenance. Enough said on that but I think I see a communication misunderstanding on WOT setting.
WOT is determined in level flight. Setting the pitch to get as close to 6800 as you can without allowing it to exceed 6800 should give you a static rpm of about 6300 and a takeoff rpm of 6500-6600 rpm which is where a properly tuned 447 develops its maximum horsepower. Cruise rpm at 80% power will be about 5400 rpm. Operating at a higher rpm serves no purpose as the engine starts to overscavenge and you develope less thrust. Operating at a lower rpm does not utilize the full potential of the engine.
The jetting charts are set up for an engine running at this pre-determined rpm. If you pitch the prop for a lower operating rpm you will find that it is operating rich under load. If you correct the jetting for this low rpm condition you will find that on a partial throttle descent your egt's will rise and you run the risk of a lean burn failure. Engines continually operated with a course pitched prop usually exhibit excessive carbon build-up.
It is critical that your tach be accurate for these adjustments, consider verfiying its reading with a diagnostic device.
Dennis
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