Return A Variable Day of the Week With a Variable Number of Days Between

I'm creating a calendar for calculating when we need to ship materials to different locations. Our shipping day is Friday for anything that needs to be shipped at distance, but we have 2 locations where we can ship the day before our events. I had planned to use a nested xlookup to determine the number of days before an event when we need to ship and what day of the week it needs to ship, but I can't figure out how to make it work, as I haven't used the weekday function before. I have tried, but I just can't figure it out with multiple variables. Am I on the right track? How do I make this work?