I'd suggest creating a big a$$ timetable over the summer, starting from day 1 right through to your mocks at least. Every week, or even every day you will put what topics you want to cover/what you want to achieve.
For example "Monday, summarise particle physics onto an A3 sheet poster, start studying topic x for economics and finish notes on topic y for biology". It will take a lot of time making the timetable (which is why i recommend doing bits over the summer) and it is bound to change a bit through the academic year. But it's super super helpful and something I wish I did. It really helps you give structure to your revision. (Use Excel to make a timetable).
Day one you probably don't even want to revise 1.5 hours a day, literally probably 30 minutes per subject a day to do some notes on the topic you're learning will be great. Recap, make notes, understand it and you'll be good for the first couple months or so.
About a 3/4 weeks before mocks, you'll want to bump your revision time up to about 45 minutes a day per subject? I think that's sufficient given that you would've been revising very consistently beforehand. I probably did 3 hours a day, so 60 minutes per subject 3 weeks before my mocks and got ABB but hadn't done much revision beforehand.
Don't wing your mocks because they're not GCSEs, especially with these new specs where you haven't got many resources. You want to be aiming to be getting at least 80-90% on each paper if you're aiming for A*/As because these new papers are much harder and you will lose a lot more marks than past papers because you're more likely to trip up and lose marks. Yes, grade boundaries will inflate according to the student cohort but you want to secure the best grades.
Easter-ish time is when the hard work/grind commends. The amount you put in is dependant on you. Some people will do 5-6 hours a day right till the end of June while others can get by with 2-3 hours per day. Choose/do what makes you feel confident in your ability to achieve and secure A*s.
Good luck :]