How can I control the figure size or aspect ratio?
There are three basic parameters: screenratio, screenht, and sreenwd. If sreenwd is not provided, it is calculated as screenht/screenratio. The defaults are:
screenratio=0.75
screenht=10.24
For a finer control, you can use xinch= (horizontal size), yinch= (vertical size), xll=, xur=, yll=, yur= (x and y coordinates for lower-left and upper-right corners). If not provided, they are calculated from screenht and screenwd.
These parameters apply to sfcontour, sfgraph, sfgrey, sfplotrays, and sfwiggle.

What color schemes are available in sfgrey and sfgrey3?
The color scheme in sfgrey and sfgrey3 is selected by color= parameter. The default is color=I.
The picture shows different color schemes available.

Changing from uppercase to lowercase letters reverses the color scale:

Adding “C” to the colorscheme name highlights the clipped values:

These examples are taken from rsf/rsf/sfgrey.