In my opinion it's a wrong approach to optimization. There's no answer. Don't be seduced by terms like "maximize" or "sales" within the platform. They might be useful but not lead your strategy. This is keyword advertising. The highest optimization you can have is make your ad and landing page (meaning your product), matches exactly the search query. When you are giving exactly what people are looking for, that's where the sale happens. Another thing, being aware that people behave differently by device, age, and other parameters that you can control within the platform. Isolate what's not working for you, and overexpose your product in those areas which instead are highly profitable. Adwords is more art than science, from my prespective.
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