Adjust text margins

Is it possible to change the text margins? I cannot find an option for it.
Changing the setting in the file (lyrics.width) does not help. When using left aligned text, only the right margin is changed with that setting.
We need to get the text more clear from the screen edges. The defaults is too close to the edge for us.

It would be great if such a setting setting could be done per song (or per theme). For some backgrounds, it also looks better to change margins. Say for instance you have a picture that includes of a cross and you don’t want to project over the cross.
An adjustable text box (drag the margins) would be even better.