The settings I use are available only on the retail Eddition of the game, those settings are as far as I know the best settings to be speedrunning the game :

First off you want to have a 640x480x16 resolution as your computer doesn't have to use as much processing power on display and can use it on making the game run faster. It's the same purpose for low resolution.

You might want to decrease your mouse sensibility because the game considers you're playing in a 640x480 pixels window so it'll seem like your mouse accuracy is garbage.

Inactive military units is usefull in a lot of mission where you have to quickly select spread out armies at the begening.

And without borderless it's actually quite hard to play in a 640x480 window, and you can see better in a full screen setup and be more precise.