Hi guys, I have many questions regarding this new install even though finding a wealth of information using the search function here on Hearth.com, most posts date back to 2007. I am in need of raising the floor of my masonry fireplace to the same height as the hearth so my insert will just s-l-i-d-e in place for this new insert install. The difference is the thickness of a brick, In other words my hearth is higher than the firebox by 2 1/4" Locally all I could find were clay bricks that had 3 large holes in them. I need to lay them on their side so all the holes will be facing up. Is this adequate, this means having all these holes in clay brick used as a base to rest my new insert upon? OR should I keep looking for another store that sells solid core bricks? AND do they even need to be clay? Is "concrete" brick an option? PS. I'll be posting some pictures of this install.