Keracolor or Ultracolor Plus? - Tile Advice

[europa]

I have 9.5mm porcelain tiles and contractor has asked me to get grout. He tells me grout lines are 3mm. I know i need Mapei colours 111 and 112, but i don't know whether to get Keracolor or Ultracolor plus. I don't think the contractor really cares, or has any interest in advising me for that matter - he just wants to get on with it! So i was hoping for some advice here.

PS: If i get Keracolor, i will need to choose between sanded and unsanded. At 3mm, i guess i would go for the sanded.

 

[Qwerty]

Keracolour is not heavily polymer modified and isn't flexible like ultracolour plus. What is the substrate?

 

[europa]

Keracolour is not heavily polymer modified and isn't flexible like ultracolour plus. What is the substrate?

Walls are plasterboard in one bathroom and plastered brick in the other. Floors are ply with insulation mats and electric heating cables on top.

 

[Qwerty]

I would opt for UCPlus all round in that case. I won't ask about weight limits on plastered walls......