No findings from Demo Day, as we didn't use the scenarios. Starting game was with a new guy, then I forgot to have the experienced players try them.
As for campaign rules, we need to hash out a Star-system only set of rules. But in a way that we can graft on Planetary forces later. I have TONS of map campaign rule variants from years of GW campaigns in 40K, fantasy, Necromunda, etc. The trickiest bits are how to reflect strategic system goals without handing victory to the players who get there first. And how to reflect fleet damage and recovery - you don't want a big loss to knock a player right out of playing at all.
My general principles will be that a fair deal of randomness and "fog-of-war" is a good thing, along with robust supply lines. :-)