I can set "every weekday" and "every 1st", but can't "every first work day of the month"
This is not supported. It may be in the future, but it can get complicated, as that term can mean different things to different people.
1) add script "ev 1st weekday month"
2) Make in preference option with checkbox for workdays and holidays
Thanks, yes we will consider adding this in future updates. Feel free to add this to our Votebox. http://todoist.com/Vote/
I am seeking to do the exact same thing for a task.
As mentioned by Brendon, we don't have such an option right now but we'll look into adding it in the future.
+1 for scheduling a task for every first weekday of every month (as voting isn't an option I'm just posting my +1 here)