Update (after 1.5 Years): This system works very well.
What I do now. I dont inbox my inbox at all, I just archive the tasks as metioned before.
When I have an Idea which fits an active project I directly open that project and write the idea down there in order ot minimize my inboxing.
Later when I work on a project I search for inboxing Items which fit to the project and get an automatic inspiration list.
I see my inboxing more like ideas I had in the past. If I really need to finish a project or have to work seriously on it I just open the proejct and create another “projectinbox” there. Works great for me, reduces stress.
Important: I combine this Inboxarchiving technique with the Block scheduling technique from cal newport. All big projects have a block schedule in my calendar and are referring to omnifocus which contains a lot of tasks. easy peasy since a lot of years.
