I'm a commercial flooring contractor. Ever think about using carpet tile? If you're in a mid/large metro area you should be able to find LOTS of carpet tile commercial dealers want to get rid of cheap. You can much more easily DIY and you'll use a releasable type of glue that allows for easy replacement if needed.
PS - Instead of using a metal edge, consider vinyl caps. Look at Johnsonite or Roppe commercial flooring products catalog for the many styles/colors available.
I would NEVER have residential carpet in my home or RV.