It is best to input crown and pavilion angles into HCA to reject less beautiful diamonds. We use trigonometry to calculate the angles from % data. Use angles if you have them because: %'s are often rounded i.e. 13.3% crown height becomes 13% or 13.5%. Pavilion depth % when converted to pavilion angle often understates the pavilion angle by 0.15° Scanners are not good at measuring culets; a culet reduces the pavilion depth % but does not change the pavilion angle. Sarin scanner data is better than Ogi because they calculate the angles and then scale of the %'s. Ogi works the other way round. If you only have access to % info (e.g. EGL, IGI or HRD report) then use the %'s to reject known duds, then and ask the supplier to run Sarin angle data on your short list.   If the supplier has idealscope photos or GemAdviser files of the diamond, then they are more useful than HCA.