The values plotted at the node and element centres are not plotted as real text but as poly lines. The default font-size for numbers is 0.18 cm. It can be changed using the menu Edit 
Options Plot option Size (plogeo.ini command HWER ).
In the representation of circles, the circle scale can be set manually defined by entering an amount for the circle size of 1.0 cm. This keeps e.g. representations of reaction volumes in different horizontal layers of a 3D model comparable.
If the circle scale is not defined manually SPRING calculates a maximum circle size for the largest value in the current plot. This maximum circle size can alternatively be defined in the menu Edit Options Plot options Sizes (plogeo.ini command RADI).
By checking the box Plot values = 0 these values are explicitly shown, otherwise values equal zero are ignored.