His shortcut trick, which helped him create arrays by memorizing formulae, didn't work here; he should integrate the attack pattern he wanted his Chakrams to follow, and to do this, he needed to master this Array completely.
He needed to learn about the use of every Magic Rune and then encode his attack pattern into it. He was lucky that his teacher had already created unique attack patterns that used three pillars to let Chakram bounce inside the formation and attack the opponent.