First, you need to convert the pantone color to RGB. Then I would search the system color palette file (ugcolor.cdf) for a match.
If you don't find it, I would make a copy of the system palette, and add your own custom color.
> of 216 entities, most are unnecessary.
OK, so pick some of the 216 that you don't like, and replace them with Pantone colors in a new CDF.
You still might have some problems ... getting Pantone colors to appear correctly on a monitor or a printer is not easy. You have to go through all kinds of calibration fiddling. Just because you have the RBG values correct doesn't mean the color will look correct. If your monitor or printer is not very good, the colors will never come out quite right.
RGB number is from 0 to 255. Opening ugcolor.cdf color number are Yellow 1.0000000 0.9411765 0.4941176, very different from RGB standard.
It's not very different. It's just a scale difference. Pantone RGB values are between 0 and 255, NX RGB values are between 0 and 1. So, white is (255, 255,255) in Pantone, I suppose, and it's (1.0,1.0,1.0) in NX.
In the "CDF" file you find the 5 columns
Color Name Red Green Blue Favorite location
The Red, Green, Blue values are basically your value from 0 to 255 divided by 255
So an RGB value of 203 230 200, in the cdf file will be 0.7960784 0.9019608 0.7843137
The Favorite location column information goes from 0 to 59
IF you go to File >> All Preferences >> Color Palette...
and expand the "Options" Section, there's the Information Icon (at the bottom right) that will print the info of the colors in RGB values to the Information Window. The Favorite location info in not printed here.