Whatever you decide, you must give people time to get prepared...
First Sunday of the month is gone, 2nd is coming up...
Why not have the Holiday Server as a Fun DDM in any given Sunday...?
Ranked DDM & Clan Wars are the only events I most worry about because I announce it to everyone in the clan...
** 2nd Sundays & 4th Sundays are classic; meaning, last Ranked DDM's I've seen people like Paranor, Ni, Coaxs, Teulk and many other that still remember about the events; I wouldn't suggest swapping them, if anything keep it consistent every month....