Tilers we are not, and have never done before. Choosing the Glue was a task as it will be submerged and needed to adhere to the bitumen rubber membrane. That made it expensive.
Because we were only doing a 10cm row we decided to tape the lines to reduce the amount of glue ending up on the waterproof membrane.I also then made up a jig to line up the tiles quicker as they were laid.
Because each edge length was determined by the dimensions of the block work with a bit of render over it, the tiles fitted on well and only a few needed cutting along the way.