Thanks! I've been reading that paragraph wrong.

Next question..... "when the next cut causes a decrease in rpms, this would be the best length for vertical, fun flying, etc."

With this configuration, the header would be just a bit on the short side. I thought that being on the short side would be best for racing (peaky but powerful), whereas being a bit on the long side would give a broader and more linear power curve, best for fun flying.

Which is it? Slightly short (below peak rpms) header, or slightly long (below peak rpms again) header for a wide and useful powerband for funflying?

Thanks again,

Ernie