Translate any grob in a score without side effect in LilyPond

[tran li]

Most GUI-based scorewriter applications allow users to drag items to 
arbitrary positions and presumably, creates no side effect. Here, by "no 
side effect", I mean the positional alteration of desired items does not 
affect the position of any other item on the score, which is like 
editing an SVG image in softwares like InkScape.

However, when searching for a method to do the same in LilyPond, I 
cannot find a method that is working in general. The `X-offset` and 
`Y-offset` grob properties seems to be tailored to slight positional 
modifications, but this actually creates side effect on other items, and 
sometimes even worse modifying these two properties takes no effect at 
all, such as for grob `RehersalMark`, `\once\override 
Score.RehearsalMark.outside-staff-padding = #1.5` works but 
`\once\override Score.RehearsalMark.Y-offset = #1.5` doesn't. Arbitrary 
translation can be a flexible method to precisely adjust item positions, 
so I am looking forward to a generally available and consistent method 
of doing so.

Best regards,
F. X. P.