Help With Main P3D Window Configuration

I am trying to lower the VRAM usage in P3Dv5.3.17 and this version cannot change. Currently, the specific way that I wish to do this is by causing the default/main P3D window to by default be small. I also will then lock this window to this size because other people will be using it that are not performance minded and may try to change the window size. I have found a minimum window size for some menus but no maximum window sizes. I have found a boolean to have the main screen open in full screen but not minimum screen. I have found sizes for many additional windows/menus in HTML code but not one for the main window or perhaps I missed it? Lastly, I have found the window lock boolean that hypothetically (I haven't tested it) lock a window size, you are welcome to add window lock information in case I am wrong about the window lock method. Most importantly, how/where do I change the default size of the primary P3D screen? I haven't been able to find it.

Additional VRAM performance suggestions are appreciated but are ultimately not what I am after in this thread. I know you can optimize the settings in world/light to help with this. However, settings like this will ultimately be useless if the person full-screens the main window, in my situation them doing this will destroy any other performance gains.

TL:DR

Main Objective: Lower the VRAM usage.

Method: Change Main Default Window To Small Size + Locking It To That Size