Spark fires off just fine, or atleast the timing light doesn't miss a beat.
I pulled the carb off to check the transfer slots and they were way out of whack. The secondaries were totally shut (shoulda checked that before I put it on). I had the primaries open atleast .125" to compensate. Definitely part of my troubles. So I set the secondaries to ~.020 (maybe a hair higher) and the primaries to .020 as well, reset the idle mixtures to a base of 1-turn and reinstalled everything.
After a tricky startup I got the choke kicked off and went back to setting everything. Trouble is, now it idles too fast. Even with the curb-idle screw out all the way (primaries closed) the idle is up around 1600. I suppose I now have the secondaries open too far? I figure once it cools off again I'll try .010" on the secondaries and start over again?