Hi. I only have 3 kids but I have a few thoughts for you. My first thought is that it is much easier with a baby than a toddler.
It is harder when you have little ones. My boys do more seat work (writing,math, etc.) when Noah is awake. Noah spends some of this time as "room time" where he plays on his own in his room. I just go back and forth watching all of them.
When Noah is napping, we do more one-on-one time like reading instruction and our Five in a Row work (I'll get to that in a minute).
I keep a list of what each child needs to do during the day and we get it in when we can. Some days this is by 10am. Some days we are still working into the evening.
The other thing that helps us is that we use a unit study approach for many subjects. Our family uses the Five in a Row curriculum and I can teach my boys many subjects together at their own level. It saves TONS of time. We have social studies, art, science, language arts, and even some applied math this way.
Karen will be able to help you a lot more. I'm sure that she'll see your post soon.
Blessings,
Hollie, Homeschooling mom to Eli (7yo), Kyle(5yo) and Noah(2yo, T21)