UE4 to composite an image (World Scaling Question)

Briefly speaking I’m just using UE4 to make a scene that I’m going to take an HQ screenshot of and render it out in Photoshop. I’m using Modo for modeling and Substance Painter + Designer for mapping. I’m using UE4 because I want to spend less time learning other resources (like Modo’s rendering and whatnot), spend less time rendering, and keep working in UE4 in order to get more experience in the engine.

I effectively want to render game characters in a dollhouse and have the camera looking out of it so that you can see the room that it’s in. The image is effectively 2/3rds (foreground + midground) this dollhouse and 1/3rd the room (background). I’m aware that I’ll probably have to do some serious touchups but how do I scale this? I want my lighting to be as good as it can be and to not have any weird artifacts. I’ve always read “don’t build to scale because physics will be screwy if things are too small” but I just saw the lighting livestream (Part 1) and it said not to make things to scale if you don’t have to because it’ll increase the lightmap resolution unnecessarily and not make as good a use of photon density ect. But both of those can be ignored in my case because I can scale them quite heavily because I’m not making a real-time application.

So, for as realistic as possible results, should I build the dollhouse and characters to scale or should I make it the size of a house and make the room HUGE and risk murdering my weak 2GB VRAM to the point of crashing? I may be missing something obvious or easy though. The major thing is that the dollhouse will have lights. Like a number of them. I assume I can scale them down as necessary. I’m planning on looking into Cinematics / Sequencer after I finish 3 more livestreams + Lighting Academy because theoretically they have similar expectations to mine vs realtime applications like games and archvis.

I realize this would likely be far easier to do in Modo I’m just trying to not spend an entire day waiting for it to render + at least a day learning how it all works. Not saying it’s hard; I plan on touching this all up in Photoshop to give it the look I’m going for including rendering out anything I couldn’t get working in a timely fashion / would’ve been way above scope (like certain types of VFX, modeling, hair textures, edge cleanup, whatever). This is supposed to get me about 70% there, not spit out a gorgeous film quality image. I also presume I’ll be using Post Processing pretty heavily as well.