You had a second question about using the sky RC to get timing and current and then adjust boost.

The target number the MFG provides is a well thought out number but its usually not perfect for all the reasons i mentioned previously. Boost makes up for the difference between the prediction the mfg made about the application in a laboratory (very conservative number) and what you need for your drive train, ambient temp, track, wear, ...

I discovered (maybe others have too) that if I set the end bell to say 5.6 amps and it results in 47 degrees of timing that the power/efficiency curve below 10k is not as good as if i set the end bell to something less. On the 17.5 I squeezed what i wanted out of the low rpms of the motor at about 39 degrees and it was significant. Then i trickled in timing at about 8k in the form of boost. You can look at some of the pictures i posted previously and you will see the transition point im talking about as a small notch in the torque curve.