I too have not had much success brush painting Tamiya.
In your situation I would recommend buying a "flesh tones" set. There are usually 6-8 bottles in a set. Vallejo and other brands (but not, to my knowledge Tamiya) make these. You could have a friend arrange them in order from lightest color to darkest color and then write a number on them so you could keep them in order. They are probably in the correct order in the box but that's no guarantee.
I have the Vallejo set but that is the only set I could find when I went looking. I'm sure their are reviews out there somewhere comparing the sets. It includes a tutorial on how to do shading.
In Alex Castros book "The Art of Painting Minature" there is a "recipe" for making a flesh set with Tamiya XF-15, XF-7, and XF-3. Flesh, Red, Yellow.
Just do a Google search on "flesh tone paint sets".