DDuck, I think, (tho not certain) you are going to have to redefine the textstyle. That can be done from the command line, so it can be scripted. An example script for style "Rom332" might look like the following, but omit anything in parantheses:
-style (Dash required to avoid dialog box.) rom332 (Substitute the name of your offending font.) romans.shx (Substitute the shx font you wish to use.) 0.09375 (Height Desired or 0) 0.6 (Width Factor) 0 (Obliquing Angle) no (Backwards?) no (Upside Down?) no (Vertical?)
I ran the command and parameters above at the command line and checked the style dialog box before and after. It appeared to give the results you requested.
Note: If you run these commands at the command line manually on one of your drawings, you will see that after naming the style and hitting return, your bigfont style will have a comma followed by additional info in the default offered. It is this information that needs to be removed. The only way I know of doing it is to redefine the style without that comma and the following info.
Hope this helps, tho I know it wasn't exactly what you were looking for !!