And what reason did the builder have for being worried?

Builder said " I am worried how it will take on the iron spindles being thin and where the spindles will hit when it matches up on the floor"... Problem is, builder has already installed nose pieces (not Bella Cera) and (I think) doesn't want to take them out to put in the Bella Cera.

And what do you think of the nose pieces he installed? Do they look acceptable? If not then I think you need to insist he change them. So sorry to hear of your difficulty with this. Stressful, I know.

What did you end up using? I am looking at the same flooring.