currently using auto fit, bar only feature for my small side chart. Found it extremely annoying when price is right at the top. Because whenever hover, the tool box blocks off the chart.
Good way to resolve it might be to have a feature that give expansion area base on user select %.
For example % up
(high point on chart - low point on chart ) * selected %, then chart expand that value.
Also same apply to % down
In this way, user does not need to fighting the chart all the time.