I tried all my switchless video adapters with the 605/33 logicboard.
This unlabeled generic adapter I diagrammed earlier in the thread offers two resolutions in the "Monitors" control panel's "Options..." dialog box: 640x480@60Hz and
800x600@56Hz!
The "Adapter 21" one offered the Apple list of rezzes: 640x480@67Hz, 832x624@75Hz, 1024x768@75Hz, 1152x870@75Hz (I'm doing this from memory, my notes are at work, so some of the Hz figures are questionable on this one).
Another adapter I have labeled "640x480, 832x624, 1024x768" offers those rezzes at the higher Hertzes of the Adapter 21.
I tried the 800x600@56Hz on the 10" color VGA CRT I have, and it looked great. The grayscale monitor is in pieces, waiting for the facelift on the case to be finished, so I couldn't try it with that, but I like that 800x600 is a working option after all! I definitely want to wire the video according to the diagram for my unlabeled generic adapter so I can choose from VGA and SVGA!
Next I'll try some combinations on the switchy adapters, and see if I can replicate the 640@60 and 800@56 rezzes to double check the diagram.