I managed to find the fix to get Redguard actually working properly on my Voodoo3 but then discovered that this damn issue can't be fixed: the default gamma in the game is too dark to be enjoyable and I can't find any way to adjust it brighter. Voodoo3 doesn't handle old direct commands and neither the gamma adjustments in Voodoo3 program affect the game at all.

Btw, since the voodoo3 fix for Redguard was adding banshee drivers into game folder, did they fix the issue where Redguard didn't work with Banshee at all?