When you work with such entities, do you look for already extant-ones or do you primarily work with ones of your own creation?

While there are a number of spirits/elementals/servitors out there that are well-known and some which essentially come with their own instruction manual. These are helpful. But, what do you do when you work with more complex entities like godforms? Do you research them exhaustively using primary sources, or do you do a quick Google search and think, "OK, likes pork, doesn't like her sister, the sea-goddess...check check?"

For instance, I've felt the need to extensively research godforms I want to work with, which lead to a rather limiting belief that I always needed "one more" bit of information before I could intelligently (and appropriately) approach such a being. As such, I tend to not ask for things directly for godforms, rather I've created a number of servitors that would fulfill specific tasks that a given godform would oversee and then use that servitor with the godform's blessings as it were.