I finally yanked out the Timberline, and have the BKK in place. While installing the firebrick (based off of the chart layout), I'm ending up with gaps- 1/4" to almost 1/2" on the sides. I've already re-cut one brick, and think I need to re-cut at least 2 more to tighten things up. Do I need to accomadate the cuts for expansion/contraction? Thanks, JB