I was browsing through my Pinboard archive and came across this very interesting post from Study Hacks website.
It describes a way of adding a structure to a day but it isn't simple planning and scheduling appointments in a calendar. So rather than dropping invents every 60 or 30 minutes put bigger blocks which will reflect larger types of work like writing, reading, key tasks etc.
I think this goes very well with the ideas promoted by Tony Schwartz who refers us to natural rhythms o our bodies. If you combine the two i.e. schedule though mental activities for your most creative time you will most likely get the results that you expect.
Working on such task should not only by more effective but would also be more focused.