Thanks Gran. I watched some Youtube videos and one guy used a round rasp on the end of a drill extension that helped clean up the glass before the pour. I also plan on drilling out as much as I can with a long spade bit before firing up the chain saw.Next question- What is the general consensus, Arjay or Seacast? Cost comparison? And where would I get it, I live in the Northeast.Thanks again! Hopefully I'll have some time soon to tackle this.