Request: allow the bounding box circles to be bigger as well as smaller

[JoyfulGen]

A while ago I opened #1098 because the blue resizing circles around bounding boxes were too big for Einsiedeln. And now we have a slider that allows the user to make those circles smaller and it works great!

However, today I tried MS73 on Neon for the first time and I encountered the opposite problem: the text on MS73 is just so big that the bounding box circles are way too small! So I was wondering if the basic circle size (25) could be in the middle of the slider, so that user can make the circles both smaller and bigger, as needed.