My hair is the same way. It took me 20 years to figure out how to finally unleash my wavies. I documented this in full in my first post to the boards.
I don't co-wash because it makes my hair greasy, but I have had lots of luck with everything I've been using (see my sig). I find that the epsom salt & water spritz is absolutely necessary in most of what I have experimented with so far, in addition to some sort of curl creme.
I use sulfate-free shampoo and conditioner, but I'm not completely cone-free/CG.
I've been pretty happy so far with what I've been doing, but continue to experiment a little here and there to see if I can find something even more powerful.
Oh...and I found part of the magic involved getting more layers in my hair to bring out the waves that were stronger under the top layer.
Hope this helps a little. Feel free to PM me if you want additional details. I'll get back to you when I can. Good luck!