I am not a big fan of making your
@context lists more complicated. Sure, modern software makes it fairly easy, but it is still administrative overhead that has to pay off somewhere. My suspicion is, the way modern software is build, it creates a desire for ornamenting your lists.
But I also don't get how people think it is appropriate to have a very important project going on, and _all_ you do to organise that would be a single NA reminder on some @office context. People who don't do GTD would never do that!
Let's get real. Per definition, work that is supposed to have "an impact" will take more than an NA that you may get around to do this week, somewhen, this week, maybe tomorrow, or so.
GTD provides the natural planning model and in it the question "How does success look like?" and the notion of principles and standards to work by.
"I make 20 prospecting phone calls for this project per day and I'll do them before noon" – could be a good routine for a sales project. All things considered. As an example.
How would working that impactful project really look like?