An update is in order. Shout out to
Securb for sending me a handful of picks to try out. The surprise winner is a 2.2mm thick Chicken Pick. It's the one on the right.
Sonically it's the most balanced and consistent but also the loudest of these (and Tortex). Bright and snappy attack with less chirp than the Gravity acrylic, more high end than the Big Stubby. It's much more stiff and dense than Tortex, and harder than any of these others; and yet, it felt familiar almost right away. It required only minor adjustments to get to the point where I wasn't making flubs. Putting it side by side with a Tortex, I think I've figured out why.
You can see the sharp bevel here:
And this is the business end:
But here it is head-on and from the edge compared to a Tortex:
The size and shape are nearly identical to the Tortex, but the interesting thing to me is the tip and striking edge - because of the bevel, those are almost exactly the same as the thinner picks. The white material has no flex at all, but it has noticeably less friction against the strings, so in practice it moves across them easily with a similar amount of force.
Aside from all of that, the thing I'm most impressed by so far is that I can't see any wear on this after a few hours of playing. The edge is still sharp and the tip is the same shape. I would have already gone through a Tortex by now, and I would have put visible wear on a Gravity acrylic.
I liked the Big Stubby too, another surprise, pretty easy to use. Will put more miles on all of these and see how they hold up.