CONFIG00.DAT
From Populous Wiki
Stores all of the games settings, including the ones using the cheat/debug menu.
Graphics Settings
Resolution
0x0
0x0 is the resolution it is a byte. Its ordered in lowest resolution (640 x 480) to highest resolution of your monitor.
Example 0 = 640 x 480 1 = 800 x 600
and the rest of the values you'll have to pull from the monitor.
WIP (Work in progress)