Support day-based monthly schedules for balance and scrub

[CS01-HS]

The interface recommends a monthly balance but my schedules are based on day-of-week.

Adding "First Monday", "First Tuesday", etc. as an option would be handy.

[itimpi]

I wonder if it is better to add for a ‘Custom’ type entry that supports crontab type scheduling.    That would allow a single option to allow for all scheduling options that are non-standard.

[ChatNoir]

That's something that is already available for Parity checks, should be easy enough to duplicate.