On our Oceanis 34, there are only a couple of things that fit properly in the built in cup holders. We have a set of small plastic glasses, which came with the boat, which fit perfectly. You might try the Beneteau website and browse through galley products. Or, think back, to see if you can recall instinctively rejecting them (and where you put them), if you received a set with your boat.
Small Euro sized cans, like Stella Artois (11.2 oz, 330 ml) fit perfectly.
Our table is a different configuration than yours. Ours folds down, all in one piece. For the water bottle that we like have handy all day when cruising, we added a velcro attached cupholder to the underside of the table. It's easily accessible, below our chartplotter pod, while underway. But is not really visable, if you don't know where it is, when the table is in either of its two positions.