[KHUx] Am I filling my keyblade correctly?

Hi,

As far as I understand it, you can only have 1 6* in your deck atm, so I've only levelled 1 6* of each type and have a bunch of 5* with yellow dots. Is this true/the best way to go about things? Or is there something I don't understand. I'm level 129 if that means anything.

Thanks!