If you're using Exocad, Here are the parameters for veneers/inlays/onlays that are in mine and working for me. Lithium disilicate has a little more thickness than the ZI.
I also found In the newest version on veneers, In expert , in either "crown bottoms" or "minimum thickness" ( can't remember which at the moment) there is a slider bar available to change the angle of the margin, making it sharper or thicker. Might be available for inlays and onlays as well.. Be careful not to make the margin too sharp or you'll be chipping them when they're milled! .....It's better to have them on the thick side, then rubber wheel them back when finishing.