I also think you could reimagine your workflow.
What OP described is easy to do in Illustrator could have made 10s or more variations in illustrator.
All of those could have been imported and extruded.
In the end I don’t think you need parametric control to make whole series of variable sizes, if thats the case I would actually list out all the sizes ahead of time or make 1 but get the right size first.
Once that decision is made you can overlay the text in the place holder area and extrude the text, basically extrude text after you decided overall size.