You'll get a new node called SD3 Latent Select Resolution, you can pick the x and y sizes from a list.
cd custom_nodes
git clone https://github.com/GavChap/ComfyUI-SD3LatentSelectRes .
You'll get a new node called SD3 Latent Select Resolution, you can pick the x and y sizes from a list.
Sizes cunningly borrowed from humblemikey