What Is The Right Dosage Of Micronor To Be Taken To Delay Periods?

Hello. I was prescribed Micronor (0.35mg Norethindrone tablets. USP) to delay my periods. My periods are due to start in 3 days. I am going on vacation tomorrow and I don't want to have my periods on the beach. I currently do not take any other type of birth-control (I have 2 kids & have my tubes tied). I read the other answers on this site. Some doctors recommend taking it once a day and others twice a day. Would it be more effective if I took it twice a day? The only thing my pharmacist indicated with the pills is that I have to take it at the same time every day. If it is twice a day, I was going to take one in the morning and one at night; would this work?