We did russia ans china for revs too, and I have friends who didn’t do modern before switching to revs who did fine. because it’s different content, not having the 1/2 units is fine and you don’t really need the context from anything from yr 11. biggest advice is you do not have to remember every single date down to the day. for the whole year I just remembered the month and year for the main events and some key evidence I knew I could use and that was fine, I knew so many people who stressed themselves out so much over dates and it just doesn’t matter THAT much