If anyone else would care to try this switch, I'd love to know if you found the same thing.

WAIT... i'm puzzled.

are you supposed to use just one thumb or the other for the space bar? i just performed a test (i put honey on alternating thumbs then typed to see if the space key got sticky... [the reason for this extreme, BTW, is that i absolutely could NOT type at all naturally when i tried to concentrate on observing my thumbs; i wound up putting spaces within words, and my typing's bad enough as it is]).... anyhow, it would appear from my not-exactly-scientific experiment that the thumb i use for the space key is whichever one typed the last character in the preceding word. OTOH, i never took a typing class, so this is probably completely wrong.