Thanks for the tips, Young1.
To wrap things up here, the car is back together and running smooth once again. Some things I noticed during this process:
- Next time I'll make sure I drain more coolant than I think I need to. I followed a nice write-up that suggested draining the coolant using the hoses that connect to the plenum/throttle body. I still needed to pull some more to get down below the injector housing level - found out the hard way and spent a bunch of extra time cleaning up coolant. Definitely worth a little more effort at the beginning to avoid cleanup later.
- Old plenum gaskets completely fell apart on the way out. Possible that the last person to be in here added some adhesive...lots of cautious time spent cleaning off the surfaces with a scraper. I applied some silicone spray to the top surface of the new gaskets prior to installation - hoping next time I'm in here it will at least be easier to remove the gaskets, if not enable re-use.
- The valley was gross! Clearing out the drain was much overdue. I did find a plenum screw I had dropped (and a MAP sensor bracket screw someone before me had dropped).
- Solenoid contacts shined up nice with the die grinder stone, and were needed (I'm at 40k miles or so). I have to imagine the starter sitting in a little bit of the valley "soup" wasn't helping either. Feeling more confident in avoiding "no starts" moving forward.
- While the service manual is handy - this forum is just as useful. We're lucky to have access to such a community.
I will say it's nice to have a successful plenum pull under my belt. Nice boost of confidence to understand the effort required, so that the next time it doesn't seem so daunting.