cryrid is right. Micromesh is completely polygon-dependant. What you could do is use the ZRemesher function to generate a mesh with less polygons whilst preserving the silhouette.
At it's most basic, when the smoothed normals for a mesh are calculated, each vertex simply grabs the flat/geometric normal of all of the polygons that it belongs to and averages them together to get it's smoothed normal. But you can weight the contribution of each polygon to that final average to try and get different -…
Nobody remembers the good old Polygon Counter utility ? ( Utilities Panel->More...->Polygon Counter, you can put it out to your main utility button set ) Even got a polygon budget slider you can adjust, so that you see when you hit the limit on an object