I generally have 2 or 3 under the age of 2, 2 or 3 under 3, and any others are 4 (6 kids in total). Once a week I have an 8 month old as well. My circle time doesn't last very long (15 minutes absolute max.), but I think it's a good learning experience for the younger ones, just in teaching them to sit in one place (they each have a mat to sit on). I usually put the baby in my lap, and the next two youngest ones on either side of me. I sit cross-legged, and tuck one foot of each of my young ones under either knee (my knees, if that makes sense). Their feet aren't trapped or squished, but it reminds them to sit close to me and to sit still. If they get distracted, I just redirect them to what we're doing. It works out quite well, and the kids enjoy it. For craft time, the youngest ones go in high chairs. I help them first, so they finish in 5 or 10 minutes. They then go play while the older ones continue with their craft.
It is harder to work with younger ones on focused activities, but I think they're capable of doing it most of the time. And the parents love it
