I finally realized that the under-inked spot moving across my cards was caused by a spot on one of the rollers that wasn't inking up, probably because of some left-over crisco from the last time they were cleaned. The only fix was to clean the rollers and start fresh. It was already 11pm so I said Fuck it! and quit for the night.
My next day off I got up early and tried again. This time everything was glorious! I listened to an awesome Jefferson Airplane album (volunteers) while I printed and everything was just great. Prints were coming out like this:
I also noticed on day two that lino blocks are slightly lower than lead type, so I stripped the masking tape wrap from my trucks and it really improved how well the block was inking.
Day two was a hit! I ended up printing about 500, that's quite a lot! Thanks Jefferson Airplane!
Here's another picture of the press looking pretty: