planning ot use Bal micro flex grout as opposed to wide joint grout..is this ok? I'm bit concerned about the grout holding in the wide grout lines as previously I've seen the grout shrink back as it dries out and pin holes appear when I used normal powdered grout on 5mm lines.
for anything over 3mm joints you'll need a wide joint grout, standard wall grouts usually are only good up to 3mm no matter what they say on the bag.