Barry, I tried the current demo version with my Lynx 60. I purposfully tried exactly what you are talking about because of my experience of cutting from Corel. The results were the same as cutting directly from Corel.
You can smooth points in Corel and Corel Trace by using the "Curve Smoothness" option in the properties bar. You can also use a little Kamikaze smoothing by changing the "curve resolution" in the "HPGL Export" section of the options when preparing to save or plot.
A Curve resolution of .004 is typically recommended for most operations but I'm comfortable with .01, I also recommend setting pen velocity based on manufacturers recommendations for the materials you are cutting. Generally 35 cm/sec is acceptable but I tend to speed things as high as 50 cm/sec. on cast.
You want to leave your plotter units alone, those just mess up your scaling.
To test my settings, I draw a 3" X 3" 64 sided star and plot it out. Over draft (sharp, erratic points on inside corners) and under draft (rounded points on outside corners) can usually be corrected by adjusting pen speed. Jerkiness from too many points can be smoothed by decreasing the plotter resolution, I call it the Kamikaze method because you never know which points will be eliminated until you plot it. In fact, I'm really not sure how they do it, it just works and for most jobs, I'm okay with it. For finer jobs, I'll stick to the higher resolution settings.
I have a drawing I'll modify for your use to test your setup, complete with jerky circle and star!