Ah... the magical attraction of contests...
As I understand it, a title screen would basically be one single giant sprite. No, wait. An object can be 32 "Byte Wide", so that is 64 pixels in "160B", right? So I'd have 2 64 and 1 32 pixel wide sprites.
I understand Dans docs thus far that I can have 4 color bits here per pixel in "160B", but nowwhere it says which bit combinations target which of the 24 color registers.
all this is explained (nicely) in the atari 7800 software guide: http://www.classic-games.com/atari7800/softguide.html