I agree with Steph, you may just not be able to cowash. There are a lot of us who have to use a low poo or something similar because our hair ends up weighed down. For instance, I don't really have hair that gets weighed down, but I get the best hair when I use CHS Treatment Shampoo (that specific shampoo isn't CG, but most people who use it find that it's more gentle than a lot of low poos). I would try out a few low poos, and see how your hair does with those.
2b, fine texture, normal porosity & elasticity (CG as of 12/2011)

Low-poo: UFD Rich & Funky
Cowash: VO5 Kiwi Lime
RO: Tresemme Naturals, Aubrey Organics GPB, Ion Effective Care, MillCreek Keratin
PT/DT: IAgirl's PT, GVP CB
LI: KCKT, Cure Care, CJ CCCC Lite
Styling: Curl Keeper, As I Am Jelly, UFD Curly Magic, CJ Curl Queen, TIGI Strong Hold Mousse


^^ day 1 of going CG; avatar = 6 months later