Heres some low quality pictures and some dimensions. I used
this website to work out the hole positions. I wanted the flute to be in the key of E330 to combine well with guitars. I drilled six holes to make the diatonic major scale the natural playable scale without shading or embouchure change.
The embouchure hole is 11mm in diameter, the inside diameter of the flute shaft is 14mm and the wall thickness is about 5mm all around. The bamboo node near the embouchure hole acts as the cork. I may have drilled a bit too far from the node but this should only change where the 'dead spots' in the flutes range are and not reduce the hole flute to a dead spot.
Anyway, I'm going to reread the flute section of my Arther Benade acoustics book and see if I can find where the problem lies. Looks like a while before I'll be building one of
these.
I've also included a couple of pictures of the blowing edges of my other attempted flutes. These are basically simple hollow tubes with holes and a sharp edge.