Hi Ricky - ref your PM about scaling the background, two pictures:
The monkey is the same size, but the background HDRI is “scaled”.
How to do this:
Add a driver to the Camera’s Focal Length.
Set the Variable for the driver as the Distance between Camera and Monkey - use a Distance Variable type and set the two objects as you can see in the picture below:
Then set the scripted expression as var - this means the focal length will be the distance between the objects. You may have to vary this to suit your model, like saying it is var * 2 or var / 2 for example, to get the object the correct size. Maybe even something like 10 + var - you have to play with this to get the object the right size.
Move the camera in its local Z axis; key G ZZ value Return. This moves the camera towards or away from the object by using positive or negative values. Grabbing the camera and moving it with your mouse doesn’t work too well, it gets all jerky, but typed values do work.
Render the viewport - the Environment Image is effectively scaled.