Mask or progressive showing of GUITexture

I’m using a GUITexture to show stat bars (such as HP). I’ve seen good explanations how to use materials to progressively show GUI elements:

however, I’m not having much luck with applying that since GUITexture doesn’t have a material, but only a texture.

So far, I’m most probably going to use atlas of 10 textures with different percentage values (0%, 10%, 20%, etc), and I’m just checking is there a way to apply a mask to GUITexture that I’m not aware of.

GUITexture doesn’t have any support for this. Just use one of the other techniques instead (don’t use separate textures, that’s really wasteful).