You're very welcome. I'm glad to help out. I noticed I left out the vertical dimension for the center of the fuel valves so I replaced the first drawing with one showing that dimension. brit plumber's width looks like a good number - my edges are a little rough and depending on where I pull it from, I could probably get it to measure almost 1/8" wider. The lower flange on mine is definitely 1-1/2" though. The M3's may be wider or maybe different manufacturers had different dimensions?