Sandy,
It will be impossible to tell the standard number of days for these lot sizes, they work on calendar months.
For a monthly lot size (MB, M2, M3 etc.), you can specify in OMI4 setting the number of months that will be clubbed together.
If you intend to work on standard number of days and want to define such a lot size, you should copy TB to a ZB, and specify the number of days over there.
Best Regards,
Rajen