Having a "remainder day" is weird, but it's hard to avoid. It really sucks that 365 doesn't divide nicely into much at all. 5 and 73 are the only non-trivial answers. five 73 day months? Can't even call it a month at that point.
I guess 13x28 + 1 does indeed make most sense...
I wouldn't trust anything involving fucking Kim Dotcom lmao