I would love there being some space for a garrison (making it a sort of fort). Something like defence + outpost which gives you ~15-20 beds, radar, defence and just enough storage to have 15 guns, clips and explosives in case they get past the defence.
Between the two, you don't need much storage, as a vault is cheap and quick to build any ways, but the added beds would be good. 10 gals is small for a garrison even if you go the "baby nuke defence" way, and there's no point building two outposts since the radar component is redundant. If adding a defence gave extra gals, then they would go well together and give you another solid defensive option to go with the barracks+vaults combo.
Outpost + Defence: Less storage, less gals, some radar, less likely to have to fight the battle -> Better for quick and cheap hangar hideouts.
Barracks + Vaults: More storage, more gals, no radars -> Better for the actual base defence battle and barracks are long term better than outposts, but more expensive.