Hi Bob,
I've been using the Horizon cameras (mono and colour) since they first came out - I've never bothered with headers that show exposure time -I simply note down in the folded that I saved them in what the exposure was.
However, I'm suprised if you can't you put a header in front of each frame. For example when I do LRGB images, I tell the sequence in Atemis programme to put RED, GREEN, BLUE OR LUM in front of each frame. I can't see why it couldn't say RED (50 SECS)?
Hope this is usual and possible?
David