Well I think the best systems are the ones we make up for ourselves and your doing that based around some ideas in GTD which is great.
I'm still trying to find my system, I know it's not GTD. I know I will capture and write things down a lot, because I do that anyway.
I'm not the most naturally organized person in the world, that's perhaps what I'm struggling with personally, compared to when I was at college, that was easy. Be here then, do this now. It's when managing myself that I get lost!
Glad you fould the system that works for you and thanks for sharing that.