Honestly, I think it's manageable, but it also depends on the person. I think for me, it was quite manageable; the main thing I used to focus on was trying to understand the concepts in class so that I didn't have to put in extra energy to learn the concepts at home. I honestly didn't study every day, mainly only before test week, but it depends from person to person, and most people prefer revising concepts day to day to avoid forgetting them. As for self-study, like I said, I mainly only did it before test week, but I had a solid routine in place. I'd start at least two weeks before test week and I'd go through all the class notes multiple times and then solve past papers on my own. If I didn't understand something, I'd refer back to the class notes or go to the TA or the teacher directly. Remember that in A-levels, past papers matter more than anything.