I second this approach, both for efficiency, and ease of process. The sparge step can be used as a volume adjustment to reach intended pre boil volume. This allows you to rough in your strike water amount, and fine tune with the sparge step.I used to get around 70%, but ever since I started mashing with 1 less gallon and using that to rinse the grains, I've gone up to over 80% consistently.
Very simple and effective, just the way I prefer!