Is there a setting for the width/height of the Animation and Stimulus editor windows?
Yes, there is. The size and position of the Altia Editors can be set in the [ALTIAHOME]/defaults/extras.ini OR
in the [Windows]/altia.ini file.
The lines to add to the .ini could look something like this:
This format can be just the X/Y offset like the 3rd and 4th samples here (+300+120) or it can be the width/height and the offsets like the first two lines (450x500+495+155).
By the way, [ALTIAHOME] means where where you've installed Altia. Usually something like c:\usr\altia80. [Windows] means the Windows installation on your machine (usually c:\windows).