people that say they don't need a mark on the chain to reference where they started probably have good eyesight not like me or old dudes
I take the file out of the guide and run it over the flat spot between the teeth to make a slight groove. Easy to find each time before you start to file and lasts forever.
Sharpie works, but the sharpened teeth stick out when they come back around pretty well. Enjoy the time you sharpen and don't rush it, the chain will be much happier as a result of your time and patience.
Maybe on the rakers, but I have a light near the bench, so the grid area stands out. Whatever works best for you, I say
I took the tree light from the living room that we quit using.... It's got the bendable arm on the lower light... Works great to get light where light needs to be...