I based my estimate on the altitude I got with a modified Estes Executioner, which had the same diameter and about the same mass. I launched my Executioner on an F25, and it had a mass of 650 grams with the motor and a camera. It reached an altitude of 1,100 feet.
I adjusted the altitude based on the difference in mass and impulse between the two rockets, and got a number of 770 feet. I launched at an elevation of 900 feet and it was very humid. Maybe the difference in altitude is due to the low humidity and higher elevation of Lucerne Valley.
I should have changed my guess to 783 feet at the last minute.
Dave