Glad I could put it comprehensively.

I'm not quite sure, though, if I can properly follow your argument. What exactly do you mean by the tools evolution might have equipped us with?

From a scientific point of view I'd challenge that biology, as a part of the natural sciences, can produce reliable conclusions regarding the moral discourse, which is set within the realm of the humanities (or philosophy, so to speak). Furthermore, biology is, historically seen, an offspring of natural history (in contrast to physics as a child of natural philosophy), which renders evolution essentially a historiographical paradigm. I might add that it surely is the best one we have come up with so far regarding the development of natural life. But nevertheless, as a historiographical paradigm it already relies on presupposing certain value judgements (in the Weberian sense) rather than being able to originate them (Hayden White, for example, examined Darwin's "Origin of species" for specific narrative tropes). So my point would be that trying to derive moral principles from the evolutionary paradigm produces a category error, notwithstanding of course the various and precious contributions evolutionary research may provide to other fields of study (e.g. how our understanding of morality might be rooted in our evolutionary history).

However, the "method of 'sorting out what works and what doesn't'" is a pretty good summary of how ethical thinking and behaviour might function. So, in a certain sense, the way evolutionary research works may be an analogon to how the moral discourse can be perceived. Just as the biologist might want to find the non-random survival of random change in any given biological phenomenon (that is, explicitly, not to claim that he performs circular reasoning but rather to describe his legitimate research interest), the moral philosopher might want to find certain actions and decisions in any given situation that fit with his principles.