Dan,
I think it is not possible to combine all of these ways I have suggested in one grand sweep on a complex geometry…
I would approach the ‘y+30,300,800 test to minimize cell count while maintaining results accuracy’ should be tested on a relevant but simple geometry with a layered mesh of low cell count but finely resolved where needed. Many runs with different layering would need to be made…
I do not have the time to do that right now.
The current approach you are taking is similar to Dylans approach here At the end of that topic I was confused, but since then, I have decided that he uses a y+ value formula for each layer and he uses those values to determine how many layers he needs at any specific ER to fully encompass the turbulent BL zone… Maybe you can use his formula which he has proven to himself…