It's probably my substantially unmotivated and rather lazy side of me saying this, but wouldn't a mod of the month come across as, well...redundant?
The aforementioned Kanpachis already do a perfectly fine job of giving special attention and praise to selected mods, not to mention having the process gone through every single month would c become an incredibly redundant and repetitive process very quickly.
If this is to be a thing, I would suggest, as others have, to allow greater intervals between said sessions, because having a mod awarded every single month not only comes with its select problems, but would really lose its impact after about the 2nd or 3rd month.
If I were to suggestion for the time in-between these contests though, I'd prefer every 4-months (1/3 of the year), just because voting time in addition to the reasons I stated previously.