Oooo - I LOVE the felted join, and sign me up as another who just uses spit. I agree; it adds that personal touch that means so much.
Wanda, you might try snipping some of the plys out of each end before you felt them together. That seems to help mine with the thickness. I only do that, though, when I'm using a chunkier yarn, mostly b/c I'm just too darn lazy.