Actually if anyone is running the Epic 19Ts then they are cheating too as they have adjustable timing. Besides, you want to reduce timing on the Quad Mag Reedy as it performs better. 24 degrees is just too high.
When you are running your Quad mag, how warm does it feel after the race? Also, where are you topping out speed wise on the longest straight. Depending on the tires you use ( low foams vs standard rubbers ), don't be suprised that with the stock spur you are up in the 28 to 32 range. My tires were extremely low and I was easilly doing in the 35 range for pinions with the stock spur.
If you hoods are perfectly aligned across from each other, that will due alittle timing retardation for you when the brushes cock alittle in the hood. I would start at 18 degrees of timing and work from there with the motor.
Also, the motor seems to put out the most power when the 767s have the serrations gone. Thats what I have noticed.