>>2798081My method is to generate at 512x768 until I find one I like, then regenerate with highres fix 1.5x, then send to img2img and use Tiled Diffusion to upscale 1.5x, the final result being the resolution of pic related.
If you're having issues with running out of VRAM, I recommend using Ultimate Upscale instead of Tiled Diffusion.
I demonstrate this in my noob guide linked in the FAQ.