Watering/feeding plants

I'm planning to grow autoflower in 1 gallon pot in soil.
1) When do you water/feed the plants?
2) How much water and nutrients to give in litres/ml?

I know that you should give enough water so the water leaks out from the bottom of the pot, but roughly, what is the amount in litres/ml?

I would go with at least 3 gal but whatever you got I guess.
I have grown autos in 3-5gal honestly I think 5 gal is better my auto came out huge in a 5 gal but Im sure a 3gal will do. 1 gal might make your plant super small.

Anyway, it depends on what nutrients you're using,

Depends on your soil and what nutes you are using. Water when the soil is nice and dry. usually evety 3-4. days for me. I would guess 1 l would do it for now but just water until there is some runoff like you said.

3 gallon is big enough. It all depends on how long you want to veg the plant, your lights, your total environment. I have been growing for quite awhile and can regularly pull 2-3 oz's per square foot of growing space with a 400 watt hps (in 3 gallon containers, i train my plants in veg by tying the girls down).. Don;t expect those results at first, but with time and experience you can and will get there.