Not counting the bonus and cameo, Ayaka x Yurine has four volumes worth of content (half of 1,3,5,7,8,9 and entirety of volume 10. Mizuki x Moe has one volume of focus (half of 1 and 4). Chiharu x Izumi also has one volume (half of 2 and 6). The rest has half a volume for each couple/trio (Kaoru's group of friend actually has only one chapter)
I'm a bit sad that Ai (Ayaka and Yurine's mutual friend) and Kaoru (the girl who have had a crush on Yurine since middle school) don't have pairings of their own. They don't show up in the last chapter, or appear on any front volume cover. At first I thought Ai was paired with her astronomy senpai Maya, but nothing came of it.
I wonder how people reacted to Ayaka's design change midway through the series. Her face was rounder, and her hair much wavier at the beginning. At the end, Ayaka's hair are pretty much straightened out, except for the tips.
And what's with Mizuki still claiming Moe as her best friend when they're about to move in together? It's not like she has any reason to hide their relationship, given that a) everyone can see it, and b) this school is full of lesbians who are explicitly dating.