Thanks for the info I will check with Madcow or modify the 2.6 dia. OneWell, one method I've used is to import a similar kit and then modify it to what your rocket is. I've found that some of the older models are quite a bit different in a RockSim file than the actual measurements on my kit! Not sure why other than some of my kits are very old. Also, by modifying the file, you get to learn more about working with RockSim in my opinion. I regularly use mass override since my builds never seem to match the files anyway. I've found that having good 'weights' on the rocket really help matching the sim to actual performance.
Of course, ask here in TRF....I've shared a RockSim file or two. And check the manufacturer's site as they usually have a version.