Have you ever considered not using a palette when painting with acrylics? To instead put the paint straight from the tube onto the brush? This is a painting technique I now use most of the time. It works for me because I've moved from mixing colors on a palette to building up color through glazing.
The technique also solves the problem of paint drying on a palette. Even using a moisture-retaining acrylic palette I found I wasted paint. With cheap or readily available paint it's not much of an issue, but with paint available to me only through international mail order, it is.
Instead of picking up paint off a palette, I apply it directly from the paint tube onto a damp brush (a clean damp brush!). How much paint depends on what I'm painting. That's something you learn to judge by experience.
