In ordinary usage, “high” and “low” suffice for whistle keys that are encountered in only two sizes.
The potential for confusion really only crops up with the key of G, correct? One could use “mezzo G” for the middle one and “bass G” for the low one which would be quite clear.
It’s hard for me to think of ordinary “Bb” and “A” whistles as a “low whistles” especially since I’ve not seen their High counterparts. To me they’re just whistles. Yet since some people call them “low” perhaps their bass counterparts should be called “Bass Bb” and “Bass A”.
Something like
High G
High F
High Eb
High D
High C
(Mezzo?) Bb
(Mezzo?) A
Mezzo G
Low F
Low Eb
Low D
Low C
Low Bb or Bass Bb
Bass A
Bass G
Personally, I would like to divide them at ‘C’, like piano octaves, just makes more sense to me, but I just wondered if there was a recognised ‘official’ designation - but it seems there really isn’t.
I think soprano, alto, tenor, bass are more vocal designation than instrumental. I tried to find a diagram of a piano keyboard with the octaves. A picture always helps, I will try again. I understand why using the piano keyboard would work. I also understand Colin Goldie chart. However to keep it simple as Syn Whistle suggested I would like to put the CG chart next to a piano designation chart, then my own chart with -high-mid-low. Might need to put others along side also as my opinion of where each range begins and ends varies.
Personally I don’t see any reason to borrow systems based on the piano keyboard, choral vocal range designations, or anything outwith the whistles themselves.
As I said above “high” and “low” are sufficient for every key except for G as far as I know. (G being, as far as I know, the lowest key, and highest key, that has ever been in normal production.)
BTW it would be cool to hear the three octaves of G whistles playing together (well, at least if they were all in tune!)