Dr No[Moderator Omega - Wristscan]
37657
The more complex the calendar function . . .
. . . the better served by apertures, imho. Sorry, but I cringe at perpetuals with pointers and scads of print on the dial.
As for simple calendars with only a date, my preferences tend towards the innocuous 4:30 position . . .
. . . and the best example I can think of would be the Sinn 756 . . .
. . . which has a date at 4:00 that practically disappears into the dial.