I can't remember, but I think I kept it for Leo's. I do not care about Sistines as I do not build cath other than 1 or 2 in metro. I did not make any metro cities.
The way to hold it was to first raze the town near it and then take or at least raze the town next to it right after capture. Raze like crazy and pump out setters with rushes via disbands.
Then rush out workers. I think I was able to get it out of anarchy in a few turns with the massive lux we had.
If you want to do another way, then do not leave armies inside. Park them around the place so they cannot send in any reinforcements. If it flip capture it again and do the same.
Leader fishing should not cost you anything in terms of conquest. I had a number of elite cavs I kept in one town. I sent them out to finish off red lined units that had been blasted by arties.
I sent them back to that town to heal, until they made a leader. Then I put them in the army. When I made another elite form using vets, they came to the same town to wait their action.
That was between 4-11 elites most of the time. I never really use tanks for the job as I needed to put them into armies as fast as they came off the line.
Do not feel anything negative about your play compared to mine. I have as much experience at this game as anyone. Played Sid level for most of the time in the last two years other than SG and AW games.
Played on massive maps since back win PTW allowed 250x250 maps, so if you do not have that kind of experience, no reason to expect to do as well.