Sooo, I only started to read this recently, but I do have a bit of experience with geisha culture thanks to a dumb faux pas I committed in Gion. Basically, those Ochaya they depict in the manga are everywhere in Gion, and most of the really serious ones are never open. That is, the front of the shop is always a closed door with no signs except a lantern or a small light indicating that they're open for business. I guess there would be an identifier somewhere showing the name of the shop but that outsiders can't easily identify. There are, however, more tourist-friendly ones near the main street. I say tourist-friendly, but that is in the sense of having clear explanation in English that you HAVE to order something when you come in, and the minimum order is boiled tofu for 2,000 yen. You can have a mini-kaiseki experience for 6,000 yen, or a full one for between 10,000 to 50,000.
So naturally I went into one (alone) and went for the 12k course. The 6k course looks and feels too much like "kids' meal" and I couldn't afford the 50k one, obviously. They sat me on the bar and started serving dishes. Next to me was an honest-to-goodness professor and he was accompanied by an English-speaking off-duty Mother, but I only found this out later. Anyway, barely two minutes after I got in, a pair of geishas came inside and walked right into the private room in the ochaya. I could hear the show going on as the kaiseki dinner started getting served. Well, 30 minutes into the meal (or maybe much sooner) the faux pas happened: I didn't finish all the items in the course already served on the table. So for an embarrassingly long time I just waited there for the next course to show up and the staff waited for me to finish so they could remove the course already served in front of me. Finally the Mother and the professor figured out that the dumb gaijin didn't know he was supposed to finish the course before the next one could be served and volunteered to explain this to me. Oops.
Anyway, meal finally finished and they offered to share a bottle of sake, so we got to talking and the Mother started explaining the sounds coming from the private room. She's a Mother in the sense of a dance instructor, not a Kagai head, but she could explain well the traditional nuances of the entertainment. What surprised me was when the professor quipped that she shouldn't be doing that because she'd be cheapening what should have been 170k's worth of services. That was a holy shit moment for me, so I asked to reconfirm and the prof explained that the geiko's booking fee was 120k and her apprentice maiko's was 50k. Each of the customers in the private room (six men) also took the 32k meal option. Geisha service is expensive!
At the time I didn't have much appreciation for the kind of life geishas went through, and a 50k JPY per showing pay rate for a 17-yr-old girl sounded horribly excessive, but this manga laid things bare to me, so I can appreciate them more now. The Mother explained to me that maikos don't actually get much pay because most of that money go straight to fund their board and education. That's why being a geiko is still necessary for their career goal.