How can 'translucent' polymer clay become really translucent, if possible at all?
Based on this blog post about comparing the various brands of translucent polymer clay, it sounds like the translucent is only apparent when the clay is incredibly thin. The author prepares the clay by running it through a pasta machine. 


  I compared every polymer clay brand’s translucent that I could find. I conditioned each clay, carefully avoiding the introduction of bubbles. I rolled sample sheets in the thickest setting (#1) on my Atlas pasta machine and the thinnest (#8) that I could make (the machine goes to a #9, but I’ve never had clay come through that alive). The thick setting is about 1/8″ (3mm) and the thinnest is about the thickness of a playing card.


The thick setting, when baked, makes the clay barely translucent in all brands, so if your figures are more than 1/8" (3mm) thick, you aren't going to notice the translucency at all. 



As you can see in the image, you can just barely make out that there is text behind the clay... which is much more visible in the thin clay: