Kevin,
Your group is the only one that I am aware of that has dis-allowed the use of the inner pipe. Because of that, most of the US racers won't be much help since we have never run the motors that way. I will say, you can always hear the growl of a motor running a little bit better than the rest. Your hope is that it is on your plane
Hope you hear something from the rest of the Canucks, but I'm not sure they will want to share their secrets...
Your best bet is to do some objective testing with props and head/liner settings. Telemetry devices work well, and so do consistently measured radar readings. Keep messing up the variables till you find something that works for you. Its not rocket science, just takes a considerable amount of time and determination. Many racers would be hesitant to share what they have worked hard to learn.