I know you say it's end game content, but A Lot of Zeroes is designed as an introductory game to the series and has much simpler rules than its prequel.
This is a paradox of the whole series of games. For the most part -- (A)-Base (D)-Landing excepted -- the complexities of space travel and colonization get simpler the higher the technology level is. I am flirting with releasing A Facility with Words and Colony: Sub/title as standalone games for this reason -- both have their own character generation systems and I could introduce a different action resolution system that makes sense for each of them (if you think about it, the fast combat resolution in AFwW already is that).
But then I end up in a situation where I benefit from writing an SRD that has the rules common to all games, but the SRD won't have character generation or action resolution mechanics in it which just feels incredibly weird.
I think I know how to square the circle on this and CSt might end up being the first rules I try this with.