Hi Chris,
Sure, that should work.
Yes, looking at the block diagram in the HD44780 datasheet it does seem like you COULD actually load 8 chars to CGRAM, display them (which writes them to DDRAM) and then overwrite the CGRAM with 8 new ones, display those and so on.
Anyway, if there's no need for more than 8 at a time then you're all set.

Keep us posted!
/Henrik.