Mura himself said in the comments on Fantia that there will be a couple more episodes before the end, and that the next episode likely will feature Taniguchi-san. He also said that after the monthly releases are done, he'll irregularly make short continuations of what happened to Taniguchi-san's breasts. On another note, I do wonder with Rival-chan if the size of her breasts here is really their fully released form, given that she's still wearing the size reduction armband. Maybe there's still more to give?