Fountainfeder still has some colors in stock.
Truthfully, I'd just use the colors you have, and see how long they'll last you.
By then you can consider whether you actually want more of these inks, or look for the then available versions. Who kniws, Sailor might return to the larger ones if sales go down. 🤔
Karmachanic has a fair point about the pricing. I personally bit the bullet and bought yamadori in the smaller bottle.
My bet is Sailor either switches to larger bottles next year or drops the price on the 20ml bottle. My biggest fear is that other ink manufacturers will try to follow suit and ink prices go up across the board.
I don't think that they will walk this decision back anytime soon. The post I quoted above makes some really interesting points about it, so I'll reproduce it here in full:
Many Japanese customers only bought those "Four Seasons" inks to match seasonal special edition pens and/or to give as a small present. Now, the entire line is named Shikiori. Each pen is more explicitly associated with a specific moment of the year and a specific colour of representing that moment. The line has its own poetic mini website visually distinct from the business-as-usual main website.
I notice also a cultural difference missed by many commenters disappointed by Sailor's decision. Sailor's main objective with this change has nothing to do with greedily trying to sell smaller quantities at higher prices. It's rather a clever readjustment of the purchase experience to match their customer's aspirations. Someone at Sailor's is skilled at building on archetypes. While in America abundance is celebrated ―for instance, having so much food it can be wasted in joyous "food fights"― in Japan, there is a reverence for brief yet very accurate evocations of fleeting natural moments. Larger volumes of inks doesn't fit the ephemeral nature of those moments, quite the opposite. However, owning a smaller quantity that won't last you forever does.Think sushi not mega burger. Think haikus not sagas
There is also a built-in nostalgia in that very clean well-defined line of products. It might not suit our Western tastes but it improves Sailor's desirability in Japan.
Business inks (black, blue-black, blue) will remain in larger long-lasting bottles while gourmet inks are now more appropriately in smaller jewel-like bottles to be cherished in evanescent doses. It all makes sense for that market.
However, as I said, I wasn't trying to start yet another discussion about the rights or wrongs of that decision. Personally, I dislike it but understand the possible motives; nevertheless, I will be spending my money on something else next time.