Thanks. There seem to be fewer and fewer kits that really appeal to me, but the ones I like, I REALLY like. Guess that means I'm turning into a scratchbuilder!
Anyway, I was thinking about building it with 38mm tubes. The center would be all motor tube, and the externals would have 29mm mounts in them. So it'd fly on either a central 38mm motor, or a cluster of six 29mm's (maybe G35's), or all seven!
Airstarting is a good idea. I haven't tried electronics yet and that'd be a fun way to start. All those tubes would make for some interesting engineering solutions.
Does your friend have a Rocsim file for the 5.5" version?
P.S. It occured to me that the stock version could be a really fun kitbash. Paint it Saturn IB style, and replace the nose cone with Apogee's Apollo capsule kit (pretty sure it's the same diameter). Add some leftover detail pieces from my Estes Saturn V, corrugated sheet styrene, engine bells, USA decals, etc...
I call it "Werhner's Revenge".