Got busy this week so have not taken the heads apart yet. I'm still debating if I still want to now that I understand how VCR drums are assembled like transformers. I don't think there are any other connections inside of it that need cleaned.
I did do some more testing on Sunday, though. I hooked up the S-video output instead of composite and confirmed the comets still show up via that route. I then recorded a tape using a DTV box and then played that tape in my Panasonic DVD Recorder/VCR combo. Played perfectly with no comets or other defects, so this is just a playback issue. I also measure the resistance of the drum-to-chassis path and measured 2-3 ohms.
I have also attached two better images of what the comets look like using my Diamond VC500 capture card (No I don't watch wrestling, that's just what was on when I turned the DTV box on
). They are always within the same couple of horizontal lines on screen. Sometimes tearing shows up instead of the comets.