Hi Andy,
I suggest using Sketched curves instead of the Annotation features to
overcome this.
There may be a way to control annotation features but I am not familiar
with it. I am familiar with using Sketches with text in them either
directly on a surface or projected onto a surface to show the type of thing
you want. You get to control the text size so it looks like your top
picture. You can put those sketches onto layers and control their
visibility this way.
Hope this helps.
Regards,
*Brent Drysdale*
*Senior Design Engineer*
Tait Communications