well i ordered one of mack hoover’s white caps(hull # 947) and have it mounted on a nickel generation tube that i’ve had lying around headless for a couple of years.
it was a very good decision. this whistle does everything i wanted and more. very nice amount of wind needed(not too much and yet not over sensitive or prone to jump to the second octive), the bell note is about the best i’ve heard, no fuzziness and very pronounced, and the whistle is very even across the octives. it is the purist of pure sounds and has plenty of volume-much more than a regular gen D. she’s very sensitive also and yet you can lay into her and slightly raise or lower the pitch before dropping or jumping the octave if you desire.
i had to sharpen the F# tone hole as it was 25 cents flat, i elongated it up about 1/64 th of an inch and then made the whole hole round with a small rat tail(sorry ralph and jerry) swiss file.
as everyone has said before, it was a pleasure doing business with mack, two e-mails and the w.c. was on its’ way. i probably caught him when he had a batch made up.
so thanks mack for a new favorite whistle, it’s a special thing you’ve done 
tansy 
just thought i would add that i tried the white cap on an o’brian improved brass feadog barrel and it was spot on on the f# hole as it was on all the other tone holes. the nickel gen f# hole was a good bit smaller than the feadogs.
tansy