The main thing I would say that a book with a lot
of text should be set in a serif face, not a sans.

> The client is adamant that he wants justified type because it looks ‘neater’

Modernist mischief.

hhp

TIME TO DECIDE:

Justifed—tell the client that it looks neater, but looks un-human & reads much worse. Your word-spacing is too fluid for this sort of thing. At least hyphenate, even liberally. (I don't subscribe to anti-hyphenation, I prefer my word spaces to be as even as possible.)

Ragged Right—tell the client that this is the preferred option of the discerning professional, like yourself, and you wouldn't presume to tell him/her the "the distance between the proposed house and sewer junction" for his/her house! Or something similar.

Typeface—sans or serif: syntax would be somewhat agreeable for short to medium lengths. Is this the sort of thing to be read in one go, or for reference?

Syntax reads well for a Sans. I would agree with Kris that ragged right would be better for this face though. You might also add a bit more leading.

ChrisL

Thanks for the comments guys. Overall I agree, ragged right is definitely the way too go.

Kris, I think it would be used more as a reference. As it's for novices I can't image too many people would read this all the way through & be able to retain much of the information. Also, with the division of chapters the sections of text are generally short to medium length.

Dezcom, any thoughts as too how much more I should open up the leading?

- George

The horns of your dilemma –
Justified – reference/technical manuals often contain long/unusual* terms and hyphenating them will slow reading/comprehension.
Ragged Right – for the above reason the ragged right margin might be too ragged and will certainly require turnovers and/or takebacks to achieve a good looking page.
I think that your measure will accommodate both and as the text is in shortish paragraphs I see no reason that you shouldn't use either, that said, the bullet points probably should be set ragged right and maybe indented.
I'm not sure about using Conduit for the captions and headings in the text, it has a soft outline and, in my view, its nature conflicts with Syntax it works fine as a headline choice though.
*terms that the reader may not necessarily have come across or in this context.
Tim

I wonder if the bulleted parts can be differentiated from the main body parts a touch more. The headlines and display I feel could be more interesting and still be taken seriously. Can't wait to see it with imagery. What happens when the contrast comes away from the page numbers? Leading variety and lighter typography every now and then could be nice.

Looking good. :)

Should the first paragraph have an indent as well?

I might add that the caption could be at a smaller size. Like the line length. An easy to read page.