So what you describe is pretty close already to inbox zero. The last step is to get even more aggressive about archiving things non-to-dos and trusting that archive search box. A truly empty inbox is more important than it may seem - new items are seen by themselves, standalone, instead of as part of existing glut of shit to take care of. And it's good to have the discipline to either commit to an imperative task or just say "no" - either explicitly or via non-response.
I found that it's a disadvantage to not have the stream of activity that Inbox infinity provides. All incoming email is sorted by date so I can always see my activity.