More seriously, I normally have my tone-holes in both hands aligned with each other and play with them pointing pretty much straight up, so far as I am aware/can observe. The amount I twist the embouchure back varies from flute to flute and maybe through time too, as my own embouchure shifts about (never being really stable and consistent - I get to play too little time overall and play too many different flutes with different demands.....). My rule of thumb set-up is with the blowing edge of the embouchure slightly forward of the spine line of the tone-holes, sometimes varying farther back to at most in-line with it.

Re: Nicholson, my experience of period Nicholson's Improved flutes is that the possible forward rotation of the R hand is defined by the configuration of the long F key (if any). The Thomas Prowse example currently en route to Rick Wilson couldn't be turned out more than I'd guess 30° without the long F touch disappearing too far down the G# block to be playable. Cf: https://youtu.be/qt0GrEwGLi4

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[I used the mill's indexing head to measure the angles. But apparently not every home has a mill. No matter, I have an easy low-tech way to measure angles of rotation at:

http://www.mcgee-flutes.com/Angle%20measurement.htm[/quote]

Terry, I feel sure my home should have a mill, but I can't seem to find it at the moment.

I measured my angles, roughly, using your method. Alone at the time, so I couldn't figure it from top level, but from the centre line of the toneholes (all in line), to the centre of the embouchure, I get 40 degrees. I'm not done tweaking the position, so it moves around a bit, but that's about where i am right now. i would LIKE to be able to rotate it back a little, as tone improves, but then I have trouble covering the toneholes. I think how long ones fingers are would be a factor here, along with the other variables.

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Cheeky young whipper-snippers!

But yeah, ideally it would be good to take into account the player's posture - you certainly see some weird ones from time-to-time. I'm assuming an erect head posture, but I guess I should specify that. Nicholson also talked of that, so fair to incorporate that assumption into his approach.