Thanks for the feedback, Marmalade!
I found that the key-element is a “reference” object, something like a cube that is close to your target object.
The key-element for me is a “reference” object. An object that would be like a box where your target object would fit into it.
Set up in Cinema 4D this as cube, in the very same dimensions.
In Photoshop, create an square or rectangle that is in that ratio width to heights—for the given view you like to have it. A side view of a box 200 heigh and 400 wide has a ratio of 1:2, that is pretty much all you need. Sorry if I explain too detailed here, but after all, we are in a forum, and the experience differs, so I keep it that way.
This image is then applied in the background, while the cube is in wireframe view (Viewer Window>Display>...) with the Size and Offset sliders you need now to match that cube to the square/rectangle in the image.
That is in a nutshell all. It might take a while, but after a few set ups you will feel more savvy with it.
Of course a complete discussion (tutorial) of this theme will contain more details and tips, but I hope that supports your work already a little bit.
If there is any question, please ask (Q&A forum), I’m happy to answer.
All the best