Of pretty much all of the pairs of girls on this site these two come across as higher up as far as the 'together, even if they're not constantly stating it' scale.
Any time one of them calls the other cute, or loves something about the other there's 0 of the usual averted gazes or backpedaling. Most of the time they're looking each other dead in the face, unflinchingly sincere. The rest of the time the joke is how over-the-top enthusiastically they say these things.
Side note after doing a quick reread: The Kill la Kill reference in chapter 3 always makes me chuckle. Partly because even if Kuran somehow managed to get a club presidency in that setting, I suspect she'd say something to get Nonon to throttle her long before Ryuko starts working her way through the various clubs.
