You don't want to choose subjects just because they scale well if you actually don't enjoy them and don't think you can perform well in them. I'll use a hypothetical example.
If you kept Maths and got a 60 raw (not saying this will happen, but just an example lol), assume it may scale up to 70.
Say if you kept PDHPE for example, you really enjoyed the subject and you got a 90 raw, even if it does scale down to 85 or whatever, it's still a better result than Maths, despite scaling down.
So I would consider which subjects I enjoy the most (which should automatically lead to good results given you put the hard work in) before scaling. Yes, scaling does matter to an extent, but not at the cost of 'forcing' yourself to do a subject just for the sake of scaling.