You mention that you send your newsletter out at 6 AM on Sundays. How did you arrive at that time? I usually shoot for mid-day some time Tuesday–Thursday; I wonder if I'm sending at the best times, though.
A/B testing :) But also, since the content straddles work and non-work, it seems like the best time regardless. I stopped testing over a year ago, so another time/day may do better, but I'm happy with it.
Plus, I can't exactly change to monday's now since it's actually called "the sunday dispatches" haha.
Do you really do this every week?