As I expected, the Merino top behaved the best with the highest ratio (and smallest singles). I spun this sample on the 16:1 pulley and plied on the 14:1.
I ended up with a 2-ply yarn that measures at about 22 wraps per inch. That's pretty tiny for me, especially since I wasn't trying especially hard to make the yarn super-thin. The top drafted out beautifully and created my most even test skein so far.
It was a true joy to spin.
I had a few more thoughts about the WooLee Winder. I think it does contribute slightly to my leadfoot tendencies, since I don't have to stop to change hooks. Kind of like when you're on the highway instead of having to stop for lights or signs, it's easy to get going a little bit ahead of yourself. (ahem.)
Worst case scenario, I need to either let the singles rest a bit before plying or run the yarn back through the wheel to remove some of the twist. Neither is fatal.
I did find that relaxing music and a small glass of wine helped me slow down. I think I just need to get used to a slightly different rhythm when spinning. Which is not a bad thing, at all.
Also, I guess complaining a little broke me of at least one bad habit. Since I wrote about it, I haven't smacked my hand into the flyer arms once. I simply approach the tension adjustment from a different angle, and have no trouble.
Happy New Year! May it bring joy and plenty of yarn your way.