but that's how I do it.
1- get all the yellows from Vallejo, CDA, Foundry, P3, AK, Liquitex, Golden, Andrea.
2- Get Pigment Binder, Flowaid, DS Water, matting agents.
3- get an empty pot.
4- add all the above in the quantaties you want to get the colour you want.
5- reply to questions on the internet.