Saturday is typically very difficult and often full. Friday at or just before check out time is usually a good time to get there. Keep in mind each weekend is different. Sometimes when I've been on Fridays it's difficult no matter the time!
Get there at checkout time, noon to up your Friday chances. Saturday tougher.
We got there around check out time on Monday and had a lot of sites to choose from but I am not sure about the Friday/Saturday aspect of your question.
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