What gauge wire to use in rewiring antique light fixtures?

I have several antique fixtures that were made using an antiquated light socket that I am replacing with a modern 120 volt standard base bulb. Some are 3, 4, 5, 6 and 8 bulb fixtures. I want to be able to use 60 watt bulbs in each socket; so I could have 8×60 = 480 watts in the big fixtures. All the ancient wiring will be replaced in the fixture lead and arms. What gauge of wire do I use? I suppose to figure the 8 bulb fixtures wire guage and the small one won’t then be unsafe. All the lighting circuits in my home are 20amp. PS electicity is magic, so please use “for dummy wording”. Thanks.