I would like to be able to save the data I enter for saddle reference points (X) and (Y) with the saddle in the standard library.
When modeling saddles I use the parameter A to define where the lowest point of the upper saddle contour is. And I guess that was also your intention. But this is not necessarily the halfway point of the saddle length. When measuring the saddle height in order to get to comparable values it is often recommended to first mark that halfway point on the surface of the saddle and then measure from the center of the bb up to that point.
As the (possible) distance between the lowest point of the upper contour of the saddle and the halfway point of the saddle length doesn't change when moving the saddle around it would be good to define where that reference point for each saddle is and then save it with that saddle model in the standard saddle library.
The same thinking applies to the Y value. I recommend to our customers when measuring their saddle height to put some board onto the saddle and measure to the underside of that board while making sure the rule "goes" through the halfway point of the saddle length. Using the board increases the repeatability of that measurement and thus makes sure you set up the same saddle at the same height across different bikes. Provided you model your saddles with a horizontal upper contour the values for parameter N and C are identical, and then Y = (C+N)/2 and can also be saved with the saddle model.
Would you please give it a thought whether you want to make this an option.