Guys, I think you are correct - the change in AoA due to the prop being tilted upwards is more significant than the difference in forward speed between the two blades. Will have to go away and draw lots of pictures to get my head around it properly, but I think I've got it - thanks!
(If anyone could explain it such that I don't need to draw loads of pictures, though, that would be even better!)
FFF
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