Selecting and moving multiple rests in 2nd voice simultaneously

Not sure if this belongs in support and bug reports or feature requests...

I'm notating a piece in 9/8 time. The second voice has eighth-note rests at the beginning of each beat. I'm trying to move all the rests down an equal distance from their default position, which is overlapping with the first-voice notes. I want to have them all move the same distance so I don't have to try to position them manually and not have them exactly line up horizontally.

I've selected all the rests using cmd/ctrl+click so they become green (screenshot 1). Then when I drag one of the selected notes, only the one note I'm dragging moves. The others turn back to black color as soon as the dragging begins and remain in their default position (screenshot 2).

When the notes are dragged, it would also be great if they can be made to automatically stay in the same position on the "X axis". In manually moving a note, there is a lot of freedom to unintentionally move it a tiny bit right or left and I'd like to avoid this happening also if possible. Is there a keystroke combination that allows for the dragging to apply to either only vertical or only horizontal movement?

Thanks as always!
Ed