My Hill/Monzani was also very quiet to start with. Despite over 25 years of playing wooden flutes I couldn’t get it to “go”. After 4 months serious work on learning how to blow it I’m now able to get enough volume out of it to play it at sessions, and I’m sure there’s more to come.
Regarding analyzing tone, I don’t know if we’ve got the software to properly look at this yet, but it should come one day. I don’t know if it’s just personal preference or if we could get some broad agreement on what is good/bad/ugly etc with room for personal preference in there as well. Just as we now have for tuning. There’s plenty of room for personal preference within the 20cent or so range of equal temperament, but if you’re 80 cents flat on low D I think most would agree that’s just ugly.
My personal opinion is that it’s a bit of a shame if we tie the desirable tone of an old RR flute to the not so desirable tuning of it. I don’t think they need to be tied together but I could be proven wrong. What about you experiment with an old flute? Get the tuning closer to equal (or some other acceptable) temperament (without getting obsessive about it) and see if you lose any of the desirable elements of the tone.
So what about people who play such instruments in tune? Are Chris Norman and Catherine McEvoy playing them wrong and the rest of us who struggle with intonation playing them right?