https://youtu.be/8WW6NHHWQQM BETTER GUIDE

Not helpful.

The description of the Widescreen Fix is indeed a bit misleading. Actually it just gives you widescreen resolution, correct FOV etc., but it doesn't fix the problem with buffered shadows.

Although the fix comes with a dgVoodoo.conf configuration file for dgVoodoo2, you actually have to install and configure dgVoodoo2 yourself to get buffered shadows.

AFAIK the flickering comes from using a newer Nvidia card (or a then newer - I'm using a 2012 GTX670 and I'm having the same problem). What helped in my case was to use the dgVoodoo2 configuration described on pcgamingwiki:

1. Download dgVoodoo2 from the official website.
2. Extract the contents to the folder of your choice.
3. Open dgVoodooCpl.exe as administrator.
4. Use the "Add"-Button in the upper right corner to add a config file in <path-to-game>\system.
5. Click the DirectX tab.
6. Under Videocard select GeForce 4 Ti 4800 from the drop-down menu.
7. Select 256 MB from the VRAM drop-down menu.
8. Click Apply and OK at the bottom of the dgVoodoo 2 application window.
9. Copy D3D8.dll file from dgVoodoo2\MS\x86 folder to <path-to-game>\system folder.

The important step for Nvidia users for fixing the flickering is step 6.

If I remember correctly I did exactly what you suggested but it didn't get rid of the issue. The game was playable and the flickering wasn't too much of a distraction - at least I had shadows now - so I finished the game with these settings.

Frankly I've given up trying to get it to run perfectly, I was content with what I got out of it. Strangely through all this I realized that a lot of people seem to have the same issue but simply don't realize it. Anyways, thanks for the input.