Hi! Fantastic that you play with your kids! Sounds great! I never heard of a guitraviol. But googled it and listened to someone playing. Very interesting! Before getting my Native American flute I search EVERY flute maker. I found highspirits.com, Odell Borg, to be BEST by far!
Native Americans think so too. Years ago I asked him to make a line of 432 Flutes, and he now does it. This is a great feature! Unless you want to get a 440 to play with other instruments. He makes them too.
The diameter is a little bigger, so the sound is amazing. If you want to check the 432s, they are called “a Earth Tone” Flutes on his site. Good luck!