G'day Mike,I reckon you should start with Chiff & Fipple - there arte endless links, including more information on making than you can digest in the next year!
I made a lot of big whistles last year - mainly to experiment with more manageable fingering spacings. I just looked at what I liked and didn't like ... and made them - but I made had some whistles back in the 1960s, so I had a background. Anyway ... I have a whole new set of ideas that I need to test when I stop doing other things ...!
If you have any specific queries, by all means, PM to me, but I think you will find site through Chiff & Fipple that cover everything you need. (I can steer you to good sites if I know what you want to do.)
Reagrds,
Bob Bolton (going back to 58 pages of music I need to learn before the Federation Ball turns me into a pumpkin!)