Should I take the SAT or the ACT to get into a magnet school?

I want to apply to LSMSA, a residential magnet school in Louisiana, but they require either ACT or SAT scores. Which of these tests would be a better choice for someone who has never taken either? Which would be easier? By my logic, the easier the test, the higher scores I can get, and higher scores would look better on my application, correct? I just have no idea which route to go. I can provide additional information if necessary. Thanks in advance for your answers!