[Feature Request] Customize where secondary characters are

Is there any way I can personalize my keeybord so I can decide myself wich symbols are where? Like this keeybord a lot, but the only thing missing for me is this. Now I have symbols visual above all the letters, and I just hold to use them. But I would love to organise and personalize them. "«»?!" this is some of the symbols I would like to put in other spots. But why nok just make it possible to reorganise all of the symbols over the characters? Or at least let me put wich ever I want above the number row (now there is no symbols or characters above)