>>49777251I'm kinda conflicted, this was an interesting photoshop experiment.
Using the 800x800 white photos from their acrylic stand pages on the PC merch store, putting their chins at the same height their tits have nearly the exact same size, mostly with Erina's sagging lower, and Airi's being wider since it seems her clothes would logically be a bit tighter and produce such an effect, so I'd conclude here that the two small differences cancel each other out, volume-wise.
But if I align them by their shoulders, Airi comes out top by a LONG shot, with heavy pups outclassing Erina by a mile.
I would have aligned them by hips as well to compare but due to their relative height differences it was pointless.
In conclusion, Airi should let me suck her tits and relieve some pressure, it's my fault after all.