Adjustable zipper foot - one of those gizmos you didn't know was missing from your life until you got one! I find it invaluable for lots of jobs where you want the needle to drop very close to the edge of something else and where the normal presser foot would either stop you seeing what's going on or prohibit the exercise entirely.
I have a 40-year old Calvin Klein coat pattern that is part-lined and part-bound inside with self-made bias binding. I've used that binding pattern piece whenever I've needed matching binding. The pattern piece looks a bit like this diagram (knocked up in Power Point, so not to scale!).
The idea is that, having decided on the width of the binding that you want (circumference of piping cord + two seam allowances, one for either edge of binding) and the length of binding you will need, you get a sheet of paper (strip of wallpaper or lining paper is fine if you don't have dressmaker's pattern paper) and draw a series parallel lines equally distanced from one another by the desired binding width. If you want a long binding fewer joins and you have fabric wide enough, you can make the parallelogram wider. If you don't, you can make it taller.
Now you draw two lines at exactly 45 degrees from top to bottom as shown. Then you put a matching-notch at the end of one row and at the other end of the row above. Add a straight of grain arrow also at 45 degrees. Now place this on your chosen fabric, cut it out and mark the rows with chalk, pins, whatever. Match the two diagonal edges at the matching-notches, pin and stitch. You will have a tube that's offset slightly. Cut along your marked lines and you'll get a long strip of binding.