Attached is a RockSim 5 file that should be close, since I dont have the details. You should expect an altitude around 1200 ft. AGL and you don't need any added nose weight.
I you want a better simulation file you need to post the details such as fin and nose cone measurements, launch lug location, and motor mount, parachute and other internal details.
Do you have a thrust curve file for the econojet F21-8w? I had to use a F24-7 which is similar..
Bruce S. Levison, NAR #69055