I use Sonlight for all mine. We have grades 2 and 1 with a K4 and a 3yo tornado lol Anyway, I'm doing core 1 with the oldest two, and my third girl is doing core P4/5. I spend about 5-6 hours a day teaching BUT there's a lot involved in that number.
One, Sonlight cores are history and cover a decent age range. With my oldest two girls, I spend maybe an hour or so doing the actual core with them. That means me reading the read alouds to them and us discussing anything they have questions about, and any mapwork that they have assigned that I choose to do. Then I work with them one on one in their readers, language arts (which I only do parts of that one), math, handwriting, and piano. I do active teaching for the lesson at hand, then she does the assignment independently while I teach her sister the lesson she has. That can take anywhere from 10-30 minutes total for a subject, depending on which kid and subject (my 7yo needs a full 30min for math, with the entire time being me actively teaching her, while she may only need 10 minutes for handwriting lesson, with the first half being instruction from me on what we are working on). For my 4yo, I spent about 30 minutes or so, give or take, doing core P4/5 with her and then we spend another half hour to 45 minutes doing math, reading, and handwriting with me directly actively teaching her almost all of that time.
I find Sonlight to be very flexible for me, as we are really super relaxed. Yes there is an IG for the cores and such, but they aren't listed as Mon-Fri with the weeks. I'm in week uhhhhhhhhh crud I have to look, but I can tell you I'm going to be doing day 5 of that week tomorrow. LOL With P4/5 I'm in week 1 since she just moved up to that core, and my 4yo is at an odd point in LA K. Taking a day off doesn't put you "behind" in my opinion, that's just a mindset for the hyper-structured school-at-home types. I'm way more relaxed than that with our lessons.
As far as workload for me and the kids, well I'm doing 2 cores with 3 different levels of LA, math, and handwriting while maintaining a full time college courseload. I spend maybe 30min at night or in the morning prepping for the next lessons, and I grade math and such as they do the work so that I can mark it off and move on OR take more time right then to work more on what they are struggling with.
I have an oldest who has multiple LDs and 2 middle kids who are accelerated learners. Sonlight is the ONLY program I've found so far that I can EASILY adjust to fit everyone's needs at the same time. I have my oldest combined in the same core as the quickest of my two middle girls right now, and I'm able to slow it down for my oldest while not holding back my second girl at the same time. I add in tons of hands-on stuff (which comes naturally to me somehow) to give us more time for my oldest to grasp the material while also giving more depth for the second girl. We spent a whole week on day 1 of week 1 just because the girls were really interested in all the material that was presented in that lesson (which I felt that book and the second book in the history portion of core 1 are just poor choices and that the core would be better without them so we dropped them and moved on in it, I think that puts us in week 7 or 8 I can't remember which) and they learned tons. The best part of Sonlight for me personally is that it isn't normal textbooks. Its REAL books. My girls relate better with regular books than they do to textbooks (trust me we did k12 for a year before going back to Sonlight) and it doesn't really feel like doing school with them. If I pull a book off the shelf to read and one sees me, she instantly tears off yelling that its school time and I get 4 kids swarming me and fighting for the best seats to see any pictures that may be on the pages (I solve this by having dd1 sit on the back of the sofa with her legs over my shoulders or laying across the back with a head on my shoulder, dd2 and dd3 on each side of me, and dd4 in my lap helping me hold the book). I have this real love affair with Sonlight obviously.
Did I miss anything? I managed to misplace my meds bottle so I couldn't find them to take today, I'm a bit foggy and having a lot of trouble concentrating and staying focused more than 2 minutes.