This is what I in theory came up with as a calendar for the option of 30 day months.

http://www.fantasy-calendar.com/cale...76904ab703b839
It takes 48 weeks for the Threadfall patterns to repeat the days of the week given a 3 day Threadfall pattern.

I'm fiddling with two different 28 day calendar at the moment, but the one for the 262 day turn lacks easy symmetry so I'm going to try to see what makes most sense.