Arian, I've never bothered making my own mixes because I figured experts already did all the research for me and created products whose ratios are meant to be right to bring out the best in hair. Granted different strokes for different folks but out of the whole collections in the market, there has got to be one that will work. I've never had any success trying to be a "scientist" and make my own products.
To me that's just like buying iron supplements, calcium supplement, biotin...and taking those assuming they are good for your hair. When you forget Vitamin A, Vitamin E, Vitamin C, MSM, Omega oils, B Complex, Inositol, Protein, PABA...all are needed for your hair. So why not get a multivitamin whose ratios are perfect for stability and absorption so you're not missing out in something.
For example water/conditioner/oil. Why? Conditioners may have oils and water already and the scientists who made the product knew that it worked best just as it is, so why are you messing up with a recipe that has been doing well as it is?
Then there's water and glycerin...where's the emollient in that? Many products with these two ingredients also have cetyl alcohol which provides an oily layer to trap the moisture that the glycerin is drawing in. So clearly, what you end up doing by trying to make your own products w/o really understanding the science behind what makes a good moisturizer is a product that might work if the conditions are very humid and then fail miserably if they are not.
So my advice is if you like those ingredients or think they might work, why not get a complete product that has those ingredients in it. All the scare stories about one ingredient being bad and so you feel you need to make your own to avoid it are nothing more than scary exaggerations. Even if you used the exact same ingredients in a store product, you would not get the same products because ingredients are not what makes a cake. Two people could start off with the exact same products and end up with different cakes...so I say leave that job to the experts and make less work for yourself.
It's what I've done, and my hair hardly occupies my mind or time from day to day.