Can you Someday/Maybe some of those projects? It seems to me that with 121 projects, surely some of those projects are simply not going to get worked on this week or this month or maybe this quarter, and therefore you could stash them somewhere away from your main lists, and perhaps review them once a week (or even less often) to see which ones should be re-activated. I tend to do this by entering a Start Date in Omnifocus, so that if I don't review Someday/Maybe when I should, the project will pop back up when the start date is reached.
Alternatively, if a lot of them are similar (say, "Review Document 1", "Review Document 2".... "Review Document 89") perhaps they could be revamped into a single "workload" project ("Make progress on document review workload") with associated lists.
I should also say that I normally don't try to choose the "most important" N/A by scanning the lists. Either I know what project is most important to me and I keep working on it, or I just work the lists, repeatedly choosing the first action that appeals to me. These are generaly "thinned" lists, because I've taken my own suggestion and tucked a lot of lower-priority projects into Someday/Maybe.
And sometimes I declare a "cleanup hour" (or "cleanup day") to knock off little tasks that will otherwise never be important enough to do, until they turn into emergencies. Then I just walk through the lists, killing every single task that I _can_ kill in a fairly short time, without worrying about priorities. (Though, again, these are the lists for projects that haven't been moved to Someday/Maybe.)
Gardener