Helpful vs. Counterproductive amount of Sleep

Alright, so I have my State swim meet this friday and saturday. I'm trying to figure out what time I should get up on friday to make sure i get enough sleep. I can wake up whenever I want since we have friday off. my question is: would it be helpful at all to sleep as much as possible? or should i wake myself up just a couple hours later than usual? is oversleeping sometimes counterproductive?
thanks for the input

In my experience over sleeping can be quite counterproductive. By all means, give your body a couple extra hours of sleep, you will most likely wake up feeling refreshed and energetic...but dont over sleep like say in to the afternoon. It will make you feel groggy and lazy all afternoon and night and then you'll just go back to sleep with a day wasted ><