To go back to the OP and the question about SSR (staff-student ratio) -- it is important, but it's tricky. I teach to grpoups of a 100+ students, and to individuals. I also teach large groups of 20, and small groups of 10 to 12.
That sort of range is typical: an undergrad will find herself in a large lecture, and then in a small group seminar or individual tutorial, or large group workshop or lab.
So the question to ask might be about modes and methods of teaching. And that's the question to ask, too, in tandem with the contact hours question.
I know applicants are now primed to ask that question, but it's also not simple. Is an 8 hour lab with a large group of students and a couple of demonstrators 8 hours of contact in a Biology degree? The equivalent in an English degree might be 8 hours all sitting in a room reading Bleak House, with a couple of lecturers roaming around. Which , frankly, would be silly.
So you need to think about how you learn, how various teaching modes facilitate that learning, and the kinds of groups of peers and times/hours you'll be learning in.
And you can discern that information, or ask. Ask about modes of teaching and learning because the mantra-- it's not school. You don't go to "lessons." It's about tutors facilitating independent learning.
One of the things I find fascinating about teaching is that I see more & more that teaching and learning are separate processes, although they often overlap or intertwine. So think about how you learn best, how you are challenged, how you are pushed to do your best work. THat might not be by visibly "active" teaching. But it may have been in a structure created by a good course structure, or facilitated by tutors.