You will get more branching if you pinch the terminal buds. You will get more growth if you fertilize them and compost them in the spring. So if you want more height fertilize them in the spring. If you want more branching pinch the terminal buds and fertilize in the spring.

Normally figs produce two fruitings: breba on past year sprouts and true-fig on new-wood of the year of vegetation, if you remove apexes remove possibility of breba (if the variety produces breba).
The repeated "fertilization, fertilization" may be is correct, seeing so poor quantity of soil in the pot, but in our (italian way) to consider the fig, is not correct.
For fig is better to add in spring a good quantity of "crude soil of field", a bit of Phosforus and Potash, but quite poor in Nitrogen. The adequate q.ty of c.s.f. carry a lot of micro and macro elements, and carries room for roots.
Correct is to fertilizzare (only) in spring.
The excessive growth in pot is not important, is important the hardening of the tree, that avoids frost damage, strong short internodes and production in fruits ..not in leaves.