Changing the length of the start of a leader line

[sergeantg]

I am suggesting that there be an option to change the length of the start of a leader line. Currently you can move the margin a negative number but it doesn't work with how short some of my labels are. It would be nice to be able to set the length. 

I am referring to the portion in the red rectangle in the image below.

I asked this on the ArcGIS Pro Questions and was told it is currently not possible.