If I wanted to train a new player so all of his white skills would reach 200%, which method will cost me less green packs?

1. powertraining 18 y.o. 3-star player
2. powertraining 18 y.o. 5-star player

(let's say that both players would be normal trainers, not that the 1st one would be a fast trainer and 2nd one a slow trainer).

Please, give me an explanation why do you think so. Thanks.