I think at some point everyone who practices yoga experiences wrist pain. With the amount of Vinyasas in Ashtanga yoga, wrist pain is almost inevitable. I have found that everyone has individual needs for this alignment.
That said, I am definitely not a yoga teacher. But, I have had a lot of different yoga teachers, teaching different yoga styles and all have said various ways of aligning my wrists in downward dog. From my experience, I either get told to align my pointer fingers to point straight or my middle fingers to point straight.
What works for me is to point my middle fingers straight, wrists aligned horizontally to my body, fingers spread wide and press through the fingertips, imaging there is a pencil that could move under my palm.
In the article, "How to Avoid Wrist Pain in Yoga" by YogaByCadance, the yoga teacher illustrates and describes how to press you hands into the yoga mat to avoid wrist injury.
Image Source: YogaByCandace