I have a Clarke D (the kind with the diamonds 
) and I have been using OXXOOO for C natural, but it does not seem to be quite on the money. Anyone have alternate fingerings for it?
Possibly try OXOXXO? I use this one sometimes for some instrument or other. I can’t recall exactly which one at this late hour.
madfifer9
Don’t mess with your fingering. Throw it aside and get a whistle that is on the money with OXX oOO. 
Ckeck it on a tuner,make the top hole bigger if its flat,or smaller by putting some tape over it if its sharp. 
Or stop being a tight wad & get a Serpent/Polly
Don’t listen to Chiff Fipple (what kind of name is that anyway?) Try OXXXOX or just OXXXOO maybe I’m crazy but these are good for me when I’m trying to play at speed. I don’t think intonation has to be spot on unless you are playing really really slow.
Trust your ears and common sense: start with oxoooo and close additional holes until it sounds right. I use oxoxxx because my (aluminium) flute likes it and I’m too busy with other stuff to remember a different fingering for each instrument.
Or half-hole.
Sonja
Yeah-- practice half holing. Even with a fine quality handmade wooden whistle which plays a perfect C nat with a oxxooo fingering 
, half holing is a skill worth mastering. You can use that skill to play a good F nat, G#, etc. It’s really not hard at all and after a while your fingers will quickly find the spot. If you’re a tiny bit off on a quick tune, nobody will hear the diff, and in a slow tune if you hit the note a bit sharp or flat, you have time to adjust and it sounds like an ornament ( bending the note). Work on it!
OXXXXO also works on some whistles. It’s just a matter of finding what works best on that particular whistle. But half holing is definitely worth getting good at. It’s helpful to have half holing as an option, even if you continue to cross finger. Some places lend themselves better to half holing, particularly where there’s a slide into the Cnat.
Best wishes,
Jerry