this off the tech sheet....but can take longer....
Coverage:Undiluted 100 - 200ml/m2 / Diluted 1:1 50 - 100ml/m2Temperature Resistance: 5°C to 38°CDrying Time: 15 -30 minutes Packaging:2.5 litre plastic containersShelf Life: 12 months, when stored in normal, dry conditions. Store between 4°C and 32°C. Protect from frost. Store away from direct sunlight.
Dont listen to the customer,pva should never be used as it leaves a coating on the wall which adhesive has an adverse reaction too,TILES MAY FALL OFF.Take heid what you have been told as you did ask for pro advice m8.