Here are some pictures of the fireplace I had ask you questions about a year or more ago.

Thanks,
Larry Showalter

While we do not generally recommend extending the surround to make the fireplace look deeper, I like the way you extended the width of the firebox without blocking the line of the covings and how you designated the "real firebox" (where you build the fire) by keeping it firebrick.

Most interestingly, I think you adjusted the firebrick arch to line up the Rumford throat in the middle. On the sides where the arch drops below the edge of the throat I can't really see if you mudded in the pockets to keep the throat streamlined but you could easily trim the back part of the firebrick arch to straighten it out and line up with the throat - an interesting alternative to mudding in the pockets. - Jim