I do a lot of "what ifs" using various designs in Open Rocket and typically I'll search the internet for a sim file of the rocket I'm interested in, or a similar rocket that I can modify. When using a sim made by someone else what types of things should I look for to verify the accuracy of the file? I fought with one sim file to get it to be stable and then I realized that someone had overridden the CG location. No matter what I did I couldn't get it to be stable with the CG location too far back. When I finally corrected that it worked fine. Besides stability, what types of things could be hidden in a file that would affect the altitude predictions?