Nate Hi there. I'm a QCE student so my Methods course may be a bit different but I still have the same idea. I would say you should definitely do yr11 in yr10 if you can.
I'm currently in Unit 4 of Methods and I'm gonna say. IT'S. SO. DAMN. EASY. That's because I do Specialist which makes it look like a baby but yeah, it's definitely manageable. You just need to understand the work when you learn it and do some revision, ensuring that you catch up in harder areas.
Doing an accelerated subject is a huge benefit in yr12 (that is if you do well) cause the stress of other subjects will be significantly lower as one subject is now gone. So I'll reinforce my point once more that you should consider it.