This is the method that works for me.
I try to paint in natural light, usually daylight, though occasionally I use my desk lamp magnifier.
I wear a cheap pair of reading glasses because at close up the eyes are not so good. Old age!
I paint six figures at a time.
I use Vallejo paints and washes and cheap brushes 000 00 and 0 sizes.
I always undercoat in black as it gives me the extra detail and shading that I like.
I go by the 3 foot rule. Usually stuff is viewed from this distance.
If it looks OK to me it generally is OK. If you want super duper detail paint in 54mm.
I try and paint three colours in a row then take a break.
I find with my method I can finish about 30 figures in a week.
In a month to six weeks it soon builds up.
I should add I also have either music on in the background or the telly on. It helps get me into the groove and distracts from the sometime repetitive bits and before you know it all those red coats are done.