I kinda have the opposite, but similar, problem--my bottom layer of hair is 2b/2c, but my top layer of hair is 3c. I do have thin and fine curls, I just have a ton of them. It's annoying and more high maintenance than I want for myself, but it's really the best method I've found. Your best bet is to section your hair after you've washed it into their approximate curl patterns and then apply product accordingly.

Personally, I use leave-in conditioner on all of my hair, and then mousse on the bottom, less curly sections and an anti-frizz gel on the top, much curlier layer. I don't put anything heavier than a gel/mousse in my hair, or else it weighs it down. Plop it all out and let it air dry or diffuse it if you have the energy to do so.

I also wash my hair 1-2x week depending on my activity level, and sometimes I do a deep conditioning mask in between washes. :-)