"Optimum" is pretty subjective. WinUAE should be configured based on your needs (e.g. playing games, programming, running LightWave 3D, creating a Catweasel disk factory, etc.).
The out-of-the-box configurations should be nominal for the platform selected, but if you plan on running RTG-friendly productivity applications, for example, you'll see a huge performance gain after enabling and using the Picasso96 and JIT features.
Trev