Select specific days for workflows / campaigns

There should be the option to select specific days of the week. This works to fix the pause issue, as well as avoid holidays and days that campaigns show lower open rates. Currently it is set up to be just workdays or all 7 days of the week. I would like to be able to look at the week and test only sending Tues through Thurs for example, or say skip Thursday and Friday if there is a holiday like Thanksgiving.