Grout Keracolor FF vs Ultracolor 1.5mm Joints

[monkey451]

Hi, we are tiling the back wall of our new shower enclosure with 33x33cm ceramic gloss tiles (photo attached). The catch is they have a mosaic effect false grout line through them, lines measuring around 1.5mm. As a result I want to use a 1.5mm spacer between tiles so there is no distinction in the gaps. Ultracolor specifies a 2mm grout line minimum but seems the better grout. Will I get away with it in 1.5mm? Is it too thick to lie in the false lines and stay-put? Would Keracolor be better? Thanks in advance.

 

[monkey451]

Bump - can anyone help please?

 

[Dave]

Hiya , the ultra colour will go into the joints ok..