Can you only go one day? No, you can go for however many days you'd like to pay the BLM to let you onto the lake bed. There is no "best" day. Go either or go both but as mentioned, if it gets blown out Saturday then we'll hold off and try to run on Sunday. Additionally, if Saturday is good and Sunday gets blown out and you didn't go on Saturday then you'd have lost out. So, pick a day and go and take your chances. Or plan on going both days and you won't miss a thing.