Advanced, Draw Setup, and change the drawing_text_size parameter to the value you want. This change affects the dimensions height (if you have dimensions you can see that changes activated immediately).
To change the font style you must change the default_font parameter (again Advanced, Draw Setup) and write arial to the default font value.
If your company has a default config.pro, you may not be able to alter that file. What I did was set up my own config.pro file which gets read in when I start Pro/E. This is what you will want to do in order to maintain your personal settings. I have different settings than what our standard config.pro file contains; keep in mind that any settings that you make in your own config.pro file will in effect take precedence over the standard settings.