As an alternative to the ball and sticks version of the Sputnik, Niel's Paper Models offers a more-realistic Sputnik paper model that you might be able to convert to a flying rocket.
Andrew:
I have the old Estes Plan #15 if it's any help.
I've been flying mine on B & C6 motors with a streamer recovery ejection pod that helps the "feather weight" recovery a little saving some flattening on the top of the ball after repeated launches
Ps the Sputnik makes a great undercarrage for flying Ghosts and downscales great as well
Here are some links. One is to some basic info on building a small Sputnik. I also have a couple of photos and one video from a COSROCS Sputnik launch.