1) Simple Entry Tool.

To select an entry you can Option-click the entry.

You can move the selection to another entry (left or right) with the arrow keys ← and →.

You can move a selected entry (note or rest) up / down with the arrow keys ↑ and ↓.

2) You can change the default vertical rest positioning (for each Layer) in

Document Options - Layers

The default vertical positioning for a rest is an inexact science. You can choose a default position which works in most situations, but there will always be measures where you need to adjust the position of the rest. That's just how it is.

Thanks for your helps, I appreciate