How should the beads look after drying? Are they always "fine" after 5 minutes? Or should I wait until they have cracks?

Often, we find that the beads dry quicker than 5 minutes, so it is advisable to check at 3 mins. Ensure that they are not shiny and try not to wait until they are cracking and overdried as beads are more difficult to resuspend and you may recover less of your sample (see Fig.1 below for an example)

Figure 1. example of dried clean up beads showing matt appearance. Well E shows a slight sheen on the beads just before completely drying.