Water needs are decreasing as the temperatures go down and the days get shorter. You can fill up a couple cups with the same mix and water one to see what the fully wet weight is, and let the other dry in the sun to get the dry weight. You should water when the cup is significantly lighter than the wet one, but do not let it get as lite as the dry one. add weight to estimate the cutting's mass as well.
I like to wait just a little tiny bit longer than Dominick has pictured to pot up; because in my experience, with a different type of cups, fresh white roots stick to the sides and are damaged when unpotted. I like to see them darken after they branch, but it is unavoidable to have some damage because if things are going well there are always fresh roots growing. But the important thing is that there are enough roots in his picture to hold the potting mix together and prevent root breakage at the connection to the cutting, which is devastating to a young cutting.