Thank you Jakob. I have now been able to try both suggestions that have been made.
DualDims does the job of showing both types of units, and can be invoked on a single dimension, or a selection of dimensions, but once invoked, those dimensions are FIXED, (not dynamic anymore), and if I am still moving things around in the design, then I must erase them, put back in dynamic dims in the system units, etc. This plugin is perfect for final documentation, but appears to make it more cumbersome during design. I hope I am using it correctly.
“Matt_Toggle_Units” does exactly what you said. Changes all dimensions in the model at once, but they remain “dynamic”.
This is the best choice for moving things around and positioning them bouncing back and forth between imperial and metric. Very nice.
Once I have the pieces done, then I can use Dual Dims on selected dimensions, and print the drawings to the shop. It is very obvious which dimensions are meant to be measured in the shop in Imperial or metric because the are almost always in nice even numbers in one system or the other.
The suggestions that you all have made allow me to achieve what I was looking for. Maybe someday there will be a plugin that combines the benefits of both of these for this type of application use.
THANKS TO ALL WHO HELPED ME!