Dado syle borders

[divvy]

All, I would love some advice on the best way to cut the dado rail style borders, the more 3 dimensional borders. I have several mitres to cut in, if it was wood I'll use my compound saw! I have an angle grinder with a diamond blade, just need to know how to get the perfect corners.

Any advice would be fantastic?

 

[divvy]

The tiles style is similar to this tile but it's hollow in the middle.

http://www.tilechoice.co.uk/proddetail.php?prod=330075

Thanks

 

[gcol]

Judge it by eye - it'll be near enough.