I dropped roughly 450-475 (my transactions list is massive!) on the tower, labs and some fuel (in addition to what you provided Rub). We'd be looking at a Tower, refinery, hangar, maint, and of course defenses. So I'd say 500-600 mill, maybe a touch less if we look for cheap gun/defense item bpc's for the tower and run off our own (smaller overall cost this way, but still a cost)