Hi @Woodspoiler ,
Welcome to the community!
@WillAdams is the vector guru around here. Until he wakes up, does this thread help?
It seems like if you use the latest version of Carbide Create (v464), use “Export” rather than “Save” in AI, and possibly set DPI to 96 in the settings (I don’t have AI, I wouldn’t know if it’s possible), you should be getting the correct dimensions upon import.
EDIT: @Bwood34 seems to be using Rhino a lot too, so maybe he can help you too.