drag coefficient

I am flying with the L1256 at an altitude of 11500ft. I have seen some posts on the forum where you enter the surface roughness polished via Openrocket to make the flight data closer to reality. I am building this rocket for a competition and the scoring depends on reaching the target altitude...

I am developing parachutes to recover two mid-power rockets with predicted descent masses of about 140 grams (~5 oz) and 280 grams (~10 oz). On larger rockets I usually make toroidal chutes and use dual-deploy. On these rockets I am going to pop the main at apogee and use flat parachutes...