After taking a look at "never been done before in rocketry" I saw the awesome picture of the third stage of a Saturn V, and it got my teenage mind going with many different things besides girls, cars, and other things. So I got to thinking, that picture was so detailed, I wonder if it would be possible to build a multi stage model of a Saturn V. First firing off 5 engines, then through gap staging, 5 more smaller ones, and finally, igniting the final stage, and the capsule would return to Earth (if still in orbit) like on the classic models. However, two things about the code have me a bit confused, the first one being about metal parts. Now, in my Estes catalog, it states "non-metal parts for the nose, body, and fins". Since this would be about scale, each stage would have the "bells" around the engine mount(s) however, with gap staging the engine is being lit within which should surely melt the plastic that's used for them (I could easily be wrong on that). If one was to use a lightweight metal like tin in the shape of the bells just for durability, would that go against the code?
Second question, there's also the weight limit for propellant of 4.4 oz. Is that just for LPR, or for all types of rocketry? As this could be a potential 11 engines, that could void it. Does this apply to the entire rocket, or is it 4.4 oz per stage?
As I currently lack skills to build something of this magnitude, it'll still stay in the back burner of my subconscious, but the clarification would be much appreciated.
Thanks for the help!