Ah ha!!! I ordered the display with a font chip, which has an 8x16 font on.
After much work that now works fine, giving me 37 lines per screen by 128 characters.
It does have a Yen/Yuan symbol instead of a dollar, but there is a variable width font with the dollar, so I can in theory swap the Yen/Yuan for a dollar on the fly later in assembly.
The viewing angle and contrast on this panel is also fa better than the previous one, image is a bit washed out still.
#LT6502b
Took another photo, tweaked settings to get the colours closer to the display.
@PaulaMaddox Looks great! How do you use that font - is it just a SPI flash that you have to read data out of before writing to the display, or is it integrated into the display controller somehow?
@emeb It's an "add on" to the display panel, the display controller (RA8889) can connect to it and grab the font from. Not all display controllers support all font chip/font size combinations (the first one had a font chip on, but the controller, RA8875, would only support 8x16 fonts, nothing smaller or bigger).