I consider water changes to be the most important factor in growth of any cichlid.
Nitrate in lakes like Arenal (were dovii get quite large) is virtually nonexistent.
So as an example, if you are doing 1 x 40% water change per week and your nitrates are 20ppm, I believe it will grow slower than if you do 2 x 30% water changes per week and your nitrates are 10 to 15 ppm, or it will probably grow faster if you do 3 or more 40% water changes per week, and nitrate are below 10ppm.
I tended to do a 30-40% water changes on 1000 gallons of tanks in the states every other day, to keep nitrate at, or below 5 ppm on all cichlid tanks.
I don't think a few months in a small tank would stunt growth permanently, I have seen amazing growth spurts when fish are added to large tanks, with lots of water changes.