I am wanting to make a shower like the picture from Kholer.(see attached)

I went to the Home Depot site and found ( MS International

Hampshire Slate 12 in. x 12 in. Gauged Slate Floor & Wall Tile)

Would this work. I have read where someone else used "Honed". Will this work ok or is it a different kind?

I have a 8' foot celing, will the beam across the top cause a problem capturing moisture? There's looks to be 9'

How difficult would it be to make the top beam an arch and put tile on it?