The attached image is tip for anyone that is looking to constrain InDesign to use the width of a text field (maintaining a single line, good for a variable data field), while allowing characters to smash if they exceed the amount that would normally cause a text frame overflow. Texts in Red; are the settings that are necessary for this functionality. There is a limittation that is outlined in the graphic; that "Glyph Scaling" with no more than a Min of 50% or a Max of 200% (Paragraph Panel > submenu > Justification) is available, which limits its' full potential.
While looking over this, if you have any thoughts on how to build on these settings to allow even more control, please do reply!
I do similar with business card layouts. Handy when the layout has already been decided, without adequate forethought, and the client recruits a Greek guy.
Imagine what we could do if they brought back Multiple Masters.