Is this method really non-canonical GTD?

Somewhere, near the end, in David’s Epistle to the Geeks is a chapter on choosing/deciding what work to do at a given moment. In it he provides a spectrum of methods from planning out the day to letting it come one moment at time. It is not non-canonical to plan every minute of your day, nor is it non-canonical to put only meeting times and deadlines in your calendar.

The David points out that factors such as context, amount of time and one’s energy level should be considered in selecting your next action.

I use a blend, leaning to work on the “minimalist - hard edge” calendar approach. It allows me to consider other factors such as location/context and, more importantly, my energy level so I can select the appropriate next action. I like having the calendar only for marking out day/time specfic tasks. I like having the control to use the remaining time as I see best uses my resources and energy.

The underlying philosophy is to permit yourself to choose and do the right next action in the moment AND not to act on other next actions. This permission must also grant you the release of any anxiety that the other next actions may be dropped, forgotten or lost. Your trusted systems and workflow of collecting, processing, organizing, reviewing and doing stuff will ensure that those next actions will get their proper consideration.