I eventually managed to do a scroll texts fast enough to do them while the pixels of the scroll text were printed to the screen. It was even fast enough to have

I eventually managed to do a scroll texts fast enough to do them while the pixels of the scroll text were printed to the screen. It was even fast enough to have char combinations in the scroll text that modified its speed and direction with speeds like "one time scroll 1 pixel the next 2". One of the tricks was to do "poor" timing with NOP's by requiring an empty row of bits between each scroll text. (The text becomes unreadable anyway if there is no space between the lines)