When I started CG in '02, as my nickname says, things were not this complicated! The whole idea was to simplify one's hair care routine, CO means conditioner, so co-wash just means "washing with conditioner" so there is NO difference between that and "no-poo", just different ways people call the CG method.

Whenever possible one CO should be enough for everything, besides, "back in the day" specific co-washes did not exist yet. IMO they are an unnecessary expense because they usually cost more than a regular CO which could be perfectly fine both for washing and conditioning.

We need to keep in mind that conditioners were created to smooth the hair after shampooing because they roughen the cuticle, with full CG that won't happen, unless a person is clarifying with b.s. or ACV. BUT since most people arrive at CG with very dry or even damaged hair, at least in the beginning reapplying the CO after "co-washing" is very helpful.

Idk if you've ever watched the Wen infommercials, one product does it all (ideally). But sometimes because people don't know their real hair's properties and condition they choose the wrong CO or use too much of it, end up with greasy-looking and flat hair with lots of frizz, and some solve the problem by getting a lighter one for washing. So my advice is to not be heavy-handed when starting, you can always use more next time or even after your hair's dry by diluting a little bit with water in a spray bottle and misting your hair with it, the same goes with the gel, better to not get enough hold for one day than to end up with petrified curls!

A good way to judge if you need to reapply or use your co-wash as a LI, is how the hair feels after co-washing it. If it's slippery and detangled easily, you may actually not need more, especially if your own scalp produces enough oil. But if hair is dry due to heat or chemical processing, then it's a good idea to use more CO rather than less.