The Walton’s is a fun whistle to play and it is easier for me because it will take more air. You were perceptive on the Dixon but for the wrong reason–it uses so little air and has such good resistance that it’s actually harder for me to play. I wind up with too much stale air in my lungs and have to breath, but I have to exhale first, which makes each breath take twice as long.
I actually sometimes blow a steady stream of air out of my nose while playing the Dixon for this reason. On odd but effective way to add a little “chiff”. 
For that achingly pure whistle sound, though, the Dixon is great, and it is well in tune.
There will be some high-end whistles coming: a Sweet rosewood, an early Sweet Killourhy, a Parkhusrt E-flat (the number 1–my wife now owns it), and a Michael Cronnolly whistle (which is the loudest whistle I’ve ever encountered–it’s louder than a clarinet). The Parkhurst is a particularly sweet and easy-on-the-ears whistle for an all-metal E-flat.
Also on the lower-end side are Susatos (old style and VSB), Sweetones, Clarkes, Waltons, Clare, and Generations.
I’m also going to include a recorder–a blackwood Adege after Terton–in some comparisons. For instance, if you think a Susato sounds like a recorder, you may be surprised when you hear them back to back. (The Dixon, of all things, actually sounds like a recorder.)
I’m going to try to record and post about one comparison a week. By the way, if there are combinations of these whistles you’d like to hear, let me know, as well as if you’d like to hear a certain whistle on a certain tune.
Best wishes, and thanks for the kind comments,
–James
http://www.flutesite.com