Would the former request containing a category list be superior to the simple general request: “Source Creator, please use your high-level detective ability to find and implement the best healing benefits that will promote client happiness, life satisfaction, and longevity?”

And indeed, as you are thinking, having just posed the question to us, there is an advantage in combining the two together to state the general goal in the broad-based open-ended request, and then add a category list as examples of things likely to be a high priority for the client and their best interest, then you would have the best of both worlds. Because, again, you need to avoid the pitfall of attempting to construct a comprehensive list as that could backfire and end up restricting what the divine might do if something does not truly belong under the specified categories and might, therefore, have to be left out.