Polar curve for calculation - input L/D values
The instrument / XCtrack should use »real« polar for calculation, which would be inserted in XCtrack. Based on polar, your L/D calculation are made, taking in to account current speed/sink (with averaging), etc, etc... (competition instrument works only by inserted polar) This is highly required especially in the competitions. (e.g. final glide)
Based on that, you can have 2 widget (and also shown on the map with (1)full or (2)empty dot), which is shoving your glide at (1)optimal L/D or (2)max speed.
Kindly asking for polar data to be inserted and used for calculations.