Quality Settings - Override several textures

Going to optimize my apk I met that textures loading Ram very much.

In general I have tested Quality Settings - Texture Quality with Quarter or Half Res is shown good memory consuption for me, but also I have big atlas for NGUI wich have text atlas, and my GUI text and other settings appear with bad quality.
So I have 2 questions:

1. Do I have any way to override few texture settings and keep them full res and build others with half or quarter res automatically.
I see only possibility to override one by one all textures bunch to smaller size except my GUI text textures and build with Quality Settings - Full Res. But it is so inconvenient.

2. Do Unity3d manage texture loading unloading for Camera view for example, or I need to unload it manually? Maybe in this case I could leave better texture quality.

 

Good question..