I’m a woman with fairly small hands, although I can reach an octave + 1 on a piano. (However, I’m not getting any younger, and am in my mid-50’s already! 
Can someone tell me the amount of distance (inches preferred, but cm OK) between the 1st & 3rd holes, and between the 4th & 6th holes on an ALBA Low D whistle? How does the spacing compare to a Kerry or a Chieftain?
Thanks!
Hole 1 - 3 = 3 inches
Hole 4 - 6 = 3 inches as well.
The difference between the Alba and a Kerry Pro
is negligable, so in fingering space terms they
are identical.
Wish I could answer you, but mine is somewhere lost in the netherlands between Scotland and the US State of Mizery…er… Missouri… dratted postal vortexes! 
THEY Finally GOT HERE… but, I was mistaken… It was a Mezzo A that I had asked for, not a low D… so I can’t help on your specific question except to say that I now own three Albas, and they are exceedingly nice whistles, and the finger spacing is closer than on my other whistles I have, so it may well be the same with the D. Good luck!
I’ve got an Alba and a Chieftain low D
The E hole of the Chieftain is bigger than on the Alba, which makes that the D hole comes closer, so the Chieftain has a shorter reach.
The E hole of the Alba is smaller than on the Chieftain which makes that the D hole is lower, so the Alba has a longer reach.
I have got long small fingers, so the Alba fits me better.
I’ve got sometimes trouble to close the E hole of my Chieftain.
It’s all about what fits best for you …
Try to find somebody were you can test these whistles would be the ultimate solution. 