tiling on a plastered wall

[ski]

Hi I am looking for some advice. I am about to tile bathroom wall. Some of the wasll is the original render, looks like cement and is rock solid. I have plastered one wall and part plastered the nother wall. I have tiles which are 470 x 310x 10. Weight limit will be 29kg. I was told not to use ready mixed but powder. Nuisance to have to mix but I have bought standard set (Dunlop). The guy in the shop advised me to use Larsen Acrylic primer on the plaster. I have 2 questions how many coats of primer? neat or diluted. Cant understand instuctions that says apply adhesive when still tacky.
Do I apply primer to the cement type render? Any advice would be appreciated.

 

[Mike Mike]

Plaster can only take 20kg / m2....

 

[Perry]

But the render will be great

 

[charlie1]

How do you know your tiles are going to be 29kg per square meter?

 

[ski]

Oops made a mistake it is 20kg. I weighed tiles 16kg, allowing up to 4 kg for adhesive.