I think this is possible by means of scripting. But i am sure there is no direct methods available to do this.
And me too not expert in scripting.
I am unsure what is the purpose of your use case, but here is some suggestions.
(See Attache Picture) Assembly Top Layer shown with Pads.
I always build my Assembly Ref Des to be the correct size, Centroid located, within the Assembly Outline of the components. Thus not requiring re-sizing. These ref des texts do not need to match the Silkscreen in size or location, as they are typically only for use on Assembly Drawings and just need to be legible.
Also, utilize the Ref Des and Part Number Rotations dialog in Editor Control to maintain proper text rotations as you rotate components. It will save a ton of work and time by not having to always rotate text. All you do is select Silkscreen text and move it to a location that is not on copper pads and visible when assembled.
If you do need to change sizes of text, they can all be selected at once, Assembly and Silk, and changed through the Properties dialog.