Question About TextureSheets Efficiency in mobile Platforms

we have multiple scenes in our game and each scene have only one Material (because we think it reduces drawcalls). we used a big texture-sheet (2048*2048) and arranged uvies the way to texture our objects.
here is the texture:

and the result is like this:

first: is it efficient on memory?
second: anywhere we used gradients compression caused problems for us.

is it better to put these gradients out of the texturesheet and use them in seperate materials?

 

bottlenecks depend on the context of the entire game so we won't know if this is a better practice for you

however things to consider

1. separate RGBA from RGB
2. RGBA using PVRTC compresses horribly (even @4bpp)
3. gradients can be much smaller textures (uncompressed) and look fantastic, billinear filter will keep them smooth
4. certain gradients can just be highly simple vertex color, (your checker pattern is easily just simple geo and vertex color)
5. your entire 'green' layout can be optimized into 2 "layers" of opaque geo

• 1 gradient to handle your color rampings
• a few RGB geo polys floated above that contain your green texture mindfully painted with it's edges to give the illusion of blending with the geo below
• or ,to make it a bit easier, model a RGBA 'skirt' around those textures to blend