This was much easier than expected.
Maybe it would have been more interesting with more invasions.
For those interested in military matters:
At hard level, we get the perfect 1 to 9 ratio for elephants to foot soldiers.
For example, with 120 enemies planned, there are 12 elephants and 108 foot soldiers.
At Very Hard level, we have 14 elephants and 130 foot soldiers.
When building this city, I was wondering if the oil import would ever come up to 40/year. Seems that no... That is sad :( 25 oil is unfortunately not enough for GI+GV 10,000 pop city.