Measuring: I measured my own blinds!
Installation: I hired a professional installer.
These shades are awesome! We have a huge window in our master bedroom (nearly 70" by 58") that faces west, so it gets the hot sun all afternoon, and at night, there is a (very annoying) street lamp right outside that disturbs our sleep. So we have the light filter portion open during the day, and at night, we switch to the blackout. The ONLY problem is at this width (nearly 6 ft!), the blind/intermediate rail is SO heavy that after five years of nearly daily use, one of the lift cords has bit the dust. The shade is still useable; I was able to tie a knot in it and save it, but it doesn't extend all the way to the bottom of the window--about 3" is exposed. So I am going to order a replacement.