Hi Jim
I have a default template sheet set at scale 1:1. I tend to import single dwg so the dialogue box comes up.
In Units settings: Use Vectorworks Document units
In Model space: this scale 1:1
centre after import is checked. This generally works fine.
If it is still not to scale, try
Modify / Scale objects
If you select symmetric by distance, you can measure a known dimension with the measure on the right and type in the distance it should be in New Distance, then have scale text & Entire Drawing buttons checked.
Good luck!
Nige