Another approach which might help you is to try Timelog -
http://www.mediaatelier.com/TimeLog4/
I have my 'clients', 'categories' and 'projects' set up in a way that complements my omnifocus 'folders', 'contexts' and projects / tasks.
The combo makes for an effective tracking sheet which doesn't cut across the tenets of GTD ;-)
As well as providing a good gui for analysing where your time has gone, the Timelog output goes to an ical calendar, so you can review what has been going on in ical if you like. I have my 'timelog' calendar set with a very faint colour so it doesn't mask the others I use for planning my life.......
Using exercise as the analogy - I have no 'exercise' or 'walk the dogs' GTD tasks, but both are important both as time users, and for my performance in other areas. Whilst I use specific tools for tracking workouts themselves , Timelog tells me who much of the day is being eaten up from 'start to get changed' through to 'back at my desk'.
Hope this helps.