i found these instructions

http://widescreengamingforum.com/forum/6753/xiii

following...

Thanks for this

Can you copy and paste, as I see nothing in the forum when I clcik the link? Thank you

http://www.wsgf.org/dr/xiii

It's here now

Thanks for this.
Links change and disappear.
I wish GOG would reserve a section where it would be possible to aggregate basic information about improving old games to make them work better on modern systems.

The forums are OK for this, but information tends to get lots and is hard to find.

Just to share my experience, I changed the settings in the .ini files, and I didn't have to restart the game.