hi Mariposa,

adding more emulsifier should thicken it up a bit. also, adding thickening ingredients like carrageenan (seaweed derived), lecithin, or even cornstarch might work well. I have not tried to thicken it up, as I prefer a very thin Co for washing, but these natural thickeners are often used ehrn making body creams, so I imagine they would work well on hair.
HTH!
Have finally figured out I am a 3A! VERY fine strands. CG since 7/05!