Let's run the numbers on chapters going into the volume, because we have a pretty decent read on what goes into a volume by now.
In the current setup, with two spreads of cast intros and recap, the volume's first chapter begins on page 7, so we start with 6 frontpages.
Then we can add up the pages of the released chapters, and then add one extra page for each chapter besides the first to account for SBS and other space-filling extra pages.
The hard part is finding the number of endpages, where the UGP and ads for merch and other such stuff live. Recent volumes have had a range from 10 to 16 pages in this space. Previous twelve-chapter volumes broke trends to have less than usual though.
With this info, we can rule out another 9-chapter volume, like v104. With the shorter chapter length, there'd only be 147 manga pages in the volume. 6 (frontpages) + 147 (manga) + 8 (SBS and extras) + 16 (endpages) = 177. Way too short, unless they do a massive feature on the live action series or something.
Ten chapters, using the same formula (now with 162 manga pages + 9 for SBS and extras) comes to 193 with a large 16-page endpage range. Which is a tad narrow, but much more within the standard for manga volume.
Eleven chapters, same maths, makes a 209 page volume. But that's the point where they might start cutting endpages, so say probably anywhere from 203 to 209 pages.
And the big twelve chapters (196 manga pages + 11 SBS and extras) comes to a meaty 213 pages before adding any endpages at all. It could get as high as 229 pages if they add 16 endpages. One Piece volumes have been this big before. Hell, some 11-page volumes, back when the chapters were a consistent 19 pages, were this large.
We can't rule out much except the shortest possibility, but it gives us a good framework to use when the listing updates with the pagecount sometime in the next month or two.
10 chapters = 190 - 200 pages
11 chapters = 200 - 214 pages
12 chapters = >215 pages
(Of course, Shueisha and Oda are free to change their patterns with this kind of thing at any time, and have done so before. Even with math, nothing's set in stone until the volume comes out.)