The thing about the double spread, and this is just my talentless opinion and i don't know if it means anything, but because Jinbei is so big Oda could've put him behind Sanji in a more clear way, just like Chopper and Franky who are both huge, so they can be behind and still get attention.
However, Oda chose to not only put Jinbei in a placement where no one was blocking him from the front, he also put Jinbei right beside Luffy. So even if Jinbei really is behind, and Sanji is at the front like a lot of people are saying, Oda made the choice of puting Sanji to the side a little more, instead of right in front of Jinbei, giving him the biggest slice of the spread and the left page especially.
Now, i don't think this has any meaning on strenght or role (Vice-Captain), it could just be Oda trying to give Jinbei a lot of space since this is his first spread. But i do think Sanji got a little bit the end of the stick on this one, Brook is also close to not being in there.