What paint are you using? And cake (solid) or liquid?
What do you mean 'just don't use as much'

Most proper face & body paints should not need diluting, if its a liquid.
If its a normal solid cake, I can easily get a whle body painted totally out of a large paradise size; largest wolfe does several.
Also depends on the effect you want. If you want perly I'd suggest something like Snaz Sparkle white or Kryolan Aquacolour, one of the pearl range. If you want silver/ metallic the Wolfe. Kryolan etc are best. If you want SOLID silver the Mehron or Graftobian mixing liquids and matching metallic powders -I can send a tips email on how to use them.
Cat x