[ryndbfsrw]

Your solution is similar to mine, but I've gone a step further and put in times in my calendar when I'm available for questions/updates/requests etc. It doubles up as the admin-part of my day where I update my GTD-style inbox of tasks that may have come up and then allocate times in my calendar when I'll deal with various tasks in future.

There is a larger problem you're touching on that in most knowledge-workcompanies there is little to no attention paid to the production line process of how that work is 'produced' with the inevitable miasma of low-value busywork ('quick question, where are we with X','thoughts on X??' etc)