If you ever feel like your Revit day is just too basic and straightforward, you should definitely read this post by the RevitCat.  There are some serious formulas in place:

This technique will not work with a curved surface because it all works by calculating the actual distance from the control point to the BL corner of the pyramid and relating that to the overall length of the surface.

Read more:
http://revitcat.blogspot.com.au/2013/10/how-to-schedule-panel-locations-on-flat.html