GUItexture Borders & Pixel Inset concept

Hi Guys,

I read the documentation of the unity about GUItexture. And google through the unity answers. I couldn't understand totally about the borders & pixel insert properties.

1) From what i know pixel insert is used for aligning the GUI texture to fix the resolution, right?

2) For borders, from my understanding it's like it's more for different computer screen side like full HD 16:9 then some it's 4:3 resoltuion so it will help. 2a)But How adjusting the value to prevent the edge texture help? 2b)And if my GUI texture size is 500x400, what values should I put on each borders?

3) Lets say, i'm making a iOS games game menu, so how do the border pixel affect the game resolution, if I have set my GUItexture to the center, by putting pixel insert

X : -(sizeWidth/2) Y : -(sizeheight/2) width : width height :height

Sorry if it's seems quite confusing, i will try to explain my questions again.

Thanks in advance!