Here's an after thought:
When the kids reach the 8 weeks old mark, they do take most of the milk, so you won't be harvesting much in the evening. You can, however, separate the kids and mom for a twelve hour period, say, on the weekends, in the evening and when you have the time to make the morning trip to the barn and milk mom, then let the little ones on her for the day. Such a shift in schedule is hardly an issue, whether you or the kids take her milk isn't a problem, on the weekends you can switch time places with the kids. You will get much more milk from mom when the kids have been off her for 12 hours.
As they get older, she may make herself unavailable for nursing, but available for milking,of
course the milk volume will go down, and she may dry up sooner, but not always. So whether you or the kids "harvest", a schedule must be kept for mom's good health and continued production. This way of things isn't how to maximize your harvest of milk, but more so a happy medium for you and the kids, they do better when not forcibly weaned. They are healthier, less stressed as is the mother. If mom is fed up with them, she'll wean them herself, and you may be able to continue milking only in the evening. I have done this in the past with no issues. But in saying that, the breed of goat you choose will have much to do with it. So be sure to check into that.
Happy milking!! K