peter said:
>   Me too.

oh alright ok...

step number 1 is to
reformat them to landscape.

make the pagesize such that
a 100% page fills up roughly half of a screen.

the page should be fully readable on-screen at 100%.

however, you should expect and encourage your reader to 
actually render the page at 150% (12-point type becomes 18).

this results in bigger better ease of readability,
while retaining an entire page fully on the screen.

in fact, the reader should be able to
upsize the page to as much as 200%, and 
still not get the page-clipping that makes
.pdf useability plummet to next-to-worthless.
(this also makes your e-book useable to
older readers whose vision is going...)

having each screen display one full page,
and only one full page, is a huge advantage,
not just for the eyes&brain of the reader, but 
also because it means the cursor keys become
functional in a way that they are not otherwise,
specifically in transporting you from page to page.
(otherwise, they move you up and down within a page.)

in this regard, be generous with page-advance commands.
for example, in the reference manual, every keyword should start 
on a new page, so paging the e-book is browsing the keywords,
with each one coming up consistently at the top of the page.)

it can also be good to keep certain blocks of text together, when
possible, on the same page.  an example might be a code listing.
i don't know how easy it is (in nisus or in your own word-processor)
to specify that a unit is to be floated to the next page if necessary
to be kept intact, but this often enhances reader useability greatly.

what you're _also_ looking for with your pagesize
is one that works well when output to hard-copy.

the trick here ied printer-drivers have
options these days that will print pages 2-up, and
give you a top-bottom option as well as left-right.

another option would be to write a simple fb program that
extracts .picts from an edoc and prints them top-bottom.

(note that printing in this format somewhat makes up for
the generosity with page-breaks, which only waste half
a page (at most), and the print version of the manual still
has consistency in that the keywords will appear _either_
at the very top of the page, or at the half-way-down spot.)

you might need to experiment to get the just-right pagesize,
but you'll zero in on it fairly quickly without too much work.

once you've got the pagesize thing down,
regenerate one of the manuals, and i'll
see if i come up with any further tweaks...

-bowerbird