I've benefited so much from this forum that I feel I should pass on a discovery to help anyone stuck with installing drawer slides in the field (such as when refacing). It's very simple and very accurate.
Cut 1/2" or 3/4" stock 2-1/2" wide by the inside height of the drawer bank (about 28" is fine). For each set of drawers, you need two pieces. Now slip the piece inside the cabinet and hold it vertically against the back side of the drawer rails and against the left or right inside cabinet wall, and mark the board with an L shaped index mark for each drawer opening. Now pull the board out, lay it on the floor or bench, and install the rear brackets for the drawer slides. (I use full extension Dynaslides). You have to move the bracket over slightly from your mark so the inside of the bracket is lined up with the mark on your board, as this keeps the back side of the slide even with the stile when installing.
Now you have 3 or 4 brackets easily mounted on the board. Just take the entire board, slip it back in the cabinet, and screw it to the back wall of the cabinet. You can even start the screws when the board is out where you can do it easy! Do a separate board for left and right sides.
This is a lot easier on the back than trying to reach into the cabinet through the small drawer openings and accurately index the slide brackets.
From contributor A:
Some euro guys actually screw the slides to the bulkheads before assembly.