The higher the better.
I would think, rather than look at something like a “safe harbor” score, understand the material, and use the QBank, albeit with repetitions to understand and retain the material. That way you are better off, and have seen more of the material, so things in the exam do not faze you.
Nevertheless, however well prepared you are, after the exam, while you wait for the results – it is nerve wracking and a lot of self doubt does creep in – I can vouch for this from personal experience on L1.
CP