Finally found this simple solution to a problem I’ve had trying to get Spacey Vade running at all aspect ratio screens in Unity.
As I am running full screen effects on the main camera they can’t stretch across the whole screen, I was trying to render to texture but the performance wasn’t good.
The linked solution simply calculates and sets the Camera.rect as the game starts so my 3 x 4 aspect portrait ratio is now preserved on any screen size.
It does look great playing on my old MAME cab, only a couple of boss levels left to complete the first 32 levels and get it up on the Steam and the Apple App store.