If I have chronic hypertension, should I double up on my meds to help reduce chances to prevent damage during the flight?

No. No, doubling your BP meds may lower your blood pressure too much and make you dizzy or even make you faint; don't do it !
NO, . You should keep the same dosage if your blood pressure has been under controled. Taking a flight should not affect it. Double the dosage may cause your blood pressure too low that can cause dizziness or heart rate too slow or too fast.