Geometry for normal mapping

Hello, dear community,

I'm making a mobile game for the first time and I have never been baking a normal map before. Now I have Meshes that have about 70 000 triangles and of course, I need to retopologize them down. The Unity documentary suggests about 300 - 1500 polygons per mesh, and I would like to have something about 400 polys since I am planning to have ten or more avatars in one level. But I'm not sure what would be a good geometry for a retopologized avatar so that it looks - almost - equal to the high poly avatar after baking the normals. In the following video they create a low poly avatar even without the nouse and eyes which the high poly avatar has, and, after baking normals it looks almost equal: https://www.youtube.com/watch?v=ApzVWuPa4A4 In the images below, you can see one of my high poly avatars and the low poly draft. The low poly is not ready since I didn't! create the body yet. But would the geometry give good result for the normal map?

Yours Raja