not being smart and staying out of this one....
I don't know if this guy can pull it off or not but...
1) looking at the plugs, they are rough to say the least., im not sure why the solid tank has so much filler on the molds, round is easy to make a smooth master, renshape (model board) and a lathe.
2) Does he have plans or an electronic model of the actual rocket? Getting the OML (outer mold line) correct is one thing, making it fly is another.
3) Pragmatic details need to be figured out, weight estimates, engine mounting, parachute location and ejection system, even how do you add launch lugs to the shape. I usually have this stuff done BEFORE making the molds.
4) What is included in the kit? How much more $ need to be added to make it fly.
5) The shuttle stack inherently isn't stable. Some of the smaller rockets solve this by adding big fins to the bottom, same approach?
Just wondering about these things.