Window Resizer didn't change the game size for me, and just make the game window take up the full screen. Pressing F5 or F6 didn't change the game size either, and pressing F6 after pressing F5 didn't change anything outside of spazzing while I held it down.Eh kinda... A bit off though.
The engine is old but you can get around this with Scripts. Unfortunately it goes outside the Patch System.
As for "RPGM VX Ace 2" well that's called "RPGM MV". It uses Javascript instead of Ruby and is more friendly to web browsers
The script Towerfag uses is Fullscreen++ v2.2 for VX and VXace by Zeus81 along with a custom RGSS301.dll
Then sets the resolution to
Graphics.resize_screen(800,608)
This however is a bit off from 16:9, widescreen.
Something closer to what this old engine can handle is
Graphics.resize_screen(800,450)
Now thanks to the interface being made to a custom resolution it breaks but does fit the full screen...
While this still gives you black bars on the sides you can press F5 then F6. F5 is the command to go full screen and F6 Enlarges the screen to match.
Alternatively there is another tool you can use to get full screen Window Resizer
Windowed
Window Resizer
F5
F6
Edit: NVM. Figured it out.