>>/38673/
You could also combine thicker (for main lines) and thinner wires (for the branches). The most simple would be doing what I drew but the wires between the boxes would be thicker.
Or you could just leave the things already up and install the new (ceiling lights, extra sockets at the table). Maybe this is the most easiest, but very amateurish I know we are amateurs, still having a little standard is good, not neat and ordnung.
To be honest I can ask a pal about what kind of wires to use, about parameters of whatever devices would be in this equation, and his opinion in general. He is an actual eggsbert. I would e-mail him your photos, my drawing, and explanations, if you wish.