It's essentially the same thing. Using your example of pigs and 6 grass hills, I would probably spec that city as my HE/GG, especially if any of those hills popped a strat rez. If nothing else came out of the cities BFC, then yes, I would prioritize ENG's and prod based buildings just so I could have an additional prod city to assist in pumping out units/wonders. Hmnn, disagree with the 2nd part of your statement, as any additional food resource in a cities BFC is always a plus, whether for trade/growth, or health purposes. As for lack of cottages, hybrid economy is always better, and not every city needs to have any cottages. You'll want cottage placement priority along rivers or fresh water sources anyway.