This is a great playthrough, and very similar to how I enjoy playing these kinds of games. I hope to see it continue!
If you're looking for more research/inspiration, I just came across this pretty detailed resource about the Aerobees that might be helpful. Lots of diagrams, descriptions, and photos.
In the meantime, I've updated to 1.12.3, reinstalled RP-1, and looking forward to seeing what I come up with.
Edit: here's a link to a list of Aerobee launches from 1959 to 1963, with details about each individual launch. I've been trying to decipher the two letter codes used, with no luck. I believe they relate to the scientific purpose of the launch, for example, 4.23 US relates to Solar measurements, 4.71 UP involves Photons, 4.69 CG involves a Gas flow counter, etc. It seems GT stands for Testing, but in all cases I can't quite figure out what the first letter stands for. What system are you using for your flights? What do XT and WA stand for, for example?
Edit2: nevermind, I found a resource that lists Nasa's identification system (page 35).