Have you ever used a chain bit?
They are quite possibly one of the kindest bits out there. The chain conforms to the horses mouth , its really not that harsh.

Over the nose or under the chin would be harsher due to the leverage being used.

"Blessed are the flexible for they shall not get bent out of shape"
"You can discipline and Discourage or you can Discipline and Encourage"
"Gentle in what you do , But firm in how you do it"