Add a new ingredient to each recipe, and the result is a 'non working' copy of that potion.
eg:
Let's call our new ingredient XYZ
Gate Potion requires Alkaloid Solvent + Memento Blossom.
Now do that recipe and add an XYZ, makes "1 dose RRR Incomplete".
Repeat that 10 times and combine makes you a "10dose of RRR Incomplete".
Combine 10dose RRR Incomplete 5x = 50dose RRR
Might take a lot of grunt work to implement though
You could make the XYZ ingredient either a farmed item, or a rather expensive vendor item to deter people from going strictly 50dose on everything.
Myself personally, I would pay an extra 1000 plat per 50dose to have just 1 BBR and 1 Mana potion in my inventory, as opposed to always carrying 2 of each around as to not run out mid-raid etc.
Idk maybe the idea is reaching pretty far, but I have been tearing through Alchemy the last few days and this popped into my head.