Ask yourself about page count and chapter length.
I've referenced this book before- it's a graphic novel autobiography. It's a rather large book, being the size of more standard US comics, rather than the smaller size for Japanese manga released in the US. It's 336 pages long, and 7.1" x 0.9" x 9" big, soft cover.
By comparison, the Gravitation manga's omnibus (two traditional Japanese volumes released into one, larger print, book) is 400 pages. Another Japanese omnibus is Zelda's Ocarina of Time volumes (again 2 volumes put into one), and it's 378 pages.
Where if you look at a single print of, say Sonic comics, it's give or take 13-16 pages until a larger collection is released. And these single "chapter" or "chapter part 1" are released for dirt cheap more or less. And that's a US release example. A good portion of manga in Japan will use the 12-14page rule as a guide for just chapter parts - Saiyuki's manga being one of them. It's releases will be crazy things like "chapter 4.1b" and "gaiden 2.3a". The tankobans (the every few month releases that Saiyuki does) tend to be really sketchy and follow this shorter page count release. The proper release of the chapters later in their print form (ie being released as "Saiyuki volume #" instead of a tankoban under a certain publisher company's name) will be more finished versions (like one tanko page of Saiyuki there was a table that went right through Goku's arm, and in the later release, it doesn't because it's not a sketch).
If you're planning to release it online there's several release schedules you can follow. One page a month, one chapter a month, one page every Friday, one chapter every Friday, one chapter every 3 months (comprising of say 26 pages, double the 13 standard), one chapter every 3 months but releases 12 pages once a month.... Lots of differing variables depending on your own personal work style 
There's several threads on here that talk more about it, and how people approach it.
