Grouting tiles with ridges & priming fresh plaster walls

[woodsy1978]

Hi,

I am about to tile my bathroom wall the tiles from the picture

http://www.toppstiles.co.uk/s_product_i ... umGrey.jpg

just wondered how the best way to get grout 1mm grout properly into the gaps without getting it into all of those ridges?


My 2nd question is that I am tiling onto fresh plaster that is 12 days old, what is the best method for priming these tiles as the weight is right on the limit of about 27-28 kg per sq meter when you add the adhesive and grout weight. should I scratch the walls slightly with a wire brush, prime then with acrlic primer or a combination of the 2? I'm going to be using slow set powder adhesive

thanks