My thoughts on bus/Buss (who's got the buses) is 14 gauge stranded on the hot side and 12 gauge stranded on the neutral. The reason for the difference is the concept of a common neutral. Your switches, accessories, etc all have their own hot so there is not the same power through your hots but using the common neutral all the neutral power is returning using that same wire. Note: for my accessories, switches, etc I use 18, 20 or what ever is handy in that realm of gauge. Some I have seen on this forum go as low as 16 gauge
As far as feeders of your hot, I again use what is available around the basement and what connectors (again some on the forum swear by soldering connection), I have available. The last few feeders I ran, I used 14 gauge because I had it and I have a big supply of Blue connectors. What others use is usually in the 16 to 18 gauge range. I have also seen member use 20 or 22 gauge but that is as high as it gets and is tipping the edge.
