How do you approach scheduling when your days off fall during the week?

I have a set work schedule at 4 days a week, with 3 opening shifts falling both during the week and on the weekend. Beyond describing your schedule in your description (which many owners don't read fully when making requests), how do you set your schedule to reflect your work? I don't want to say I'm unavailable all mornings when I am free 4 mornings a week, and hate that my rating/visibility is affected by the fact I can't set my calendar appropriately. Is there any way to work around this?