So I actually tracked my diamond production for the last week.
Starting on 11/12 right after I collected all my dailies on all 5 worlds, I had 911 diamonds.
11/13 - 901, 11/14 - 961, 11/15 - 101 (Bought an expansion for 1k), 11/16 - 406, 11/17 - 644, 11/18 - 634, 11/19 - 624.
So over the week I was up 703 diamonds. During that week I spent 70 diamonds collecting on 2 worlds. And at least a couple hundred diamonds on negotiations. So I'm comfortable with an estimate of roughly 1k diamonds a week as my production estimate.