Hello I am going to build my first oven based on "2005 small commercial pizza oven w/Pat Manley" From the MHA site. (www. mha-net.org) I found thru a link on this site. W/that said I have a couple of questions. First if I look at the pics I noticed that they pulled out a course of brick on each side of the entry, Why? & there is threaded rod and c-channel on both sides, This is for strength, But dies it need to stay on the build after the motar sets up. Thanks & I hope this makes sense.