carnival73: Looking for full screen support. GOG's 6 & 7 doesn't have it.
The DOS versions of Wizardry 6 and 7 can be reconfigured into a 4:3 or widescreen output (
described here), depending on what you're wanting. For Wizardry 7 the DOS version installer is in the bonus content, not the normal installer.
Wizardry Gold doesn't have fullscreen support; the closest you can get to filling the screen is to go to the shortcut properties and set it to 640x480 mode on the Compatibility tab.
Wizardry 8 recognises widescreen resolutions but everything will be stretched from 4:3. If you don't want stretching you can set the game to run in pillarboxed 4:3 (
described here) to make the best use of the screen while retaining the correct aspect ratio.
Steam's versions of the games only differ in terms of OS support; the games' features and compatibility are the same.