I do that!!
My wife’s conditioner has the opening on the bottom, opposite of the shampoo…
I did that for mom.
I just refill the smaller conditioner bottle so I can tell the shampoo and conditioner apart.
I use markers on the lids of my meds, so i can look down into the container *I keep them in, and not have to go through all of them each time.
The brand I use makes the shampoo bottle black and conditioner white.
I buy the brand that combines shampoo and conditioner together. Saves that extra rinse.
Only buy brands in clear or translucent bottles. The shampoo is clear, the conditioner is cloudy.