so rudder must be applied throughout to remain in balance.
I diagree
Well specifically I disagree with the statement more than the reality. Shaggy Sheep said it all really. Just to add that the only reason the ball isn't centred is because you have aileron induced drag on the up wing, so therefore you use rudder when you use aileron. Some types generate significant drag so to prevent over/under bank in the turn you may need a little aileron and subsequently rudder too. My practical experience of 152s, Arrows, etc is that aileron drag is realitively insignificant and bank corrections in the turn don't cause any significant imbalance (none that my virtual clogs can accurately cancel anyway) so no need to use the feet in the turn. Come to think of it, I don't recall older designs like the Super Cub nor the Vagabond being problematic in that regard either.
I don't think the answer to the original question had anything to do with adverse yaw though.