I use a similar system and agree that start/defer dates are probably the most useful/powerful tool in OmniFocus. They have completely changed how I work.
I actually skip the “Today” perspective entirely and work directly out of a perspective called “Available,” which is very similar to @babblingdweeb’s “Actionable” perspective:
- Group By: Flagged
- Sort By: Project (Context would work just as well)
- Filter by status: Any status
- Filter by availability: Available
- Sidebar filtering: Remaining
Although the list of available items can get long, the first thing I do in the morning is skim through the list and defer all the items that I know I won’t work on that day. If I know I won’t get to it for a while, I might defer it one week (“1w”). If I want to see it again tomorrow, I will just defer it one day (“1d”). If I think I might work on it today, but definitely won’t get to it until the afternoon, I will defer it just a few hours (say, “3h” for 3 hours or “1p” for 1:00pm). This quick daily review only takes about 5-10 minutes, and I very quickly get down to a manageable list of 5-15 tasks.
I really like having the perspective grouped by “Flagged,” because then I can flag the 1-3 items that I want to work on immediately, and hide the “Unflagged” group. Once I have finished all the available flagged tasks, I go back into the “Unflagged” group and flag some more.
With a system like this, I don’t need a notification for when every task hits its start/defer date (which would quickly become unmanageable). Instead, I know I will be reminded of it because I can control exactly when each task will show back up in my main “Available” perspective. And I know nothing will slip through the cracks, because I am reviewing every available task at least once a day.