ORIGINAL: speedracerntrixie
Remember that ignition timings is determined by 3 things. Compression, nitro content and plug heat range.
There is a 4th factor that effects timing....load. A heavy load makes the engine "think" that it's either over compressed or got too much nitro.
Your earlier post shows that you already know this.....
A 5th factor..[some might argue this]...oil content, oil quality. Don't back off on the oil until you see a decrease in performance. I have run 25-30% oil in my Nelsons with great results.
The extra oil allows more aggressive tuning.