Other overblown bagpipes

He is. Third octave that is. Sean’s a squeaky fellow. From what I’ve picked up from the big brains on the Internet (McGee, Cameron, Powell, etc.) you get a more powerful first octave by opening the bore up but you lose the third a bit. Since Irish music doesn’t feature much in the way of third octave (not the ITM I’ve heard anyway) this is considered an acceptable tradeoff.
The champions of the baroque flute will be quick to tell you that a conical bore flute can perform very well in the third octave. The French flutes used in Cuban Charanga start in the second octave and go up from there - same with American Fife and Drum music. Rockstro was very post-Boehm and of course he’d run down much of what had come before him. He was quite a crank - had it in for a lot of Boehm’s innovations, too.
I have the fingering down for third ocatave E on my flutes - that’s as far as my E Baack antique 8 key will go anyway! And it has a good first octave as it happens. Some of my other flutes play those high notes very easy but have weak first octaves, as mentioned above.

Yes I was refering to LE (high) HAUTE G, mais oui, mon frere! As my first flute experience was on the “silver” flute, and I had absorbed the “lore” of that instrument, I.E., why it was based on a cyclinder bore, what had come before, etc. In 1972, I bought my first “antique” flute for 4 quid, a Keith Prowse,London, with a decidedly sharp of D tendency, It had big bore, and big fingerholes, lined with “german” silver and a silver oval around the embrosure hole. A Low C key thrown for good measure. At the time, the Keith Prowse company was a London theatre ticket agency, I’ll have to read the Langwill index, for the dates of their flute manufacture. Since I had the flute, I had to get the Rockstro book (the very last, slightly used, store copy) for another 4 pounds. I was a amazed by Rockstro’s bit about Coronel Gordon doing all the inovation and Theobald B. taking all the credit. But the fingering charts…I had many different “nach” Meyer (after Meyer, in the style of Meyer) as these German flutes were imported in great numbers (Sears & Roebuck) to the USA. The “Simple System” as these 19th century flutes are called in England, are called “Meyer System” flutes in the USA. Some of them were lower than A=440 more like A=430. One flute, a Lehrner of Munich, was the lowest with the low "B’ key. I tried to get the last 3 notes above high G and on some flutes, I got a reasonable high A. Now I only have an unmarked, slightly sharp, German (maybe American) flute that ends at D. Oh, and because it was only $50 at an antique store, a real H.F. Meyer flute in it’s original case, with swabs,cork grease cup, with an Ivory top and 2 Ivory tenon-protector cups. The man at the store thought it was an old clarinet (everybody always thinks of silver flutes as FLUTES). Well just because I can’t get more high notes, doesn’t mean somebody “out in the big wide world” hasn’t perfected the technique, but I haven’t had the pleasure of meeting her/him, OR them!
Going for those musical highs…S.F.