I have purchased 4 total, built 2. I did the D12-C6-C6 in both rockets. The first weather cocked into the wind and I looked but did not find any part of it. The 2nd was at my first high power launch and it was a nice straight flight and recovered all the parts.
I found a old C3 kit and purchased it from the yard sale here and plan to build mostly stock, just have the payload tube house electronics for seperation duty on a failed stage event. And possibly little tubes glued to the boosters that will hold a 6" plastic chute or streamer.
The other new kit will be something. I cut out basswood fins. I plan to lengthen the boosters to take the E12 motor and the 1st stage could use the AT 24/60 case.
It will have a lot going on in tbe payload: gps or rocket hunter, raven 3. This will cover finding the thing and possible stage duty/apogee event.
I plan to fiberglass the airframe and have the option to fly it on the CTI G65 long burn motor, staged to or just the sustainer.
I built and flew a couple 2 stage rockets that were inspired by the C3, I did fly a AT E20-4 to E12-8 but the delay on the booster motor was to long and it started to weather cock as it staged and was a impressive lateral looking sustainer. I also flew a few E12-E12 flights and achieved 1875' I think.
I have not had success in open rocket to estimate the altitude of such a project. But based on my other flights and accounting for the smaller diameter I would fly the AT F35w - E12-0 - E12-8 and I hope it would go around 5280'.