I want to make beads out of polymer clay. Is it a better idea to form the holes before baking, or drill them after? (I'm concerned about weird shrinkage or other effects around the hole during baking, affecting the size.)
Much simpler if you do it before.
You will always deal with some shrinkage with polymer clay, so just make sure that the hole is a bit larger than you will need it. If you are really worried, try a couple of samples and measure how much they will shrink. But it is fairly minimal, so unless you need an exact fit, it is nothing that major.