EXACTLY WHAT YOU NEED, ANDREW. Coursed instruments are referred to as "COURSED", 5-COURSED, not "10-string". You seek to raise the IGNORANCE of manufacturers of folk and rock instruments to a virtue, to a new musicological convention. The centuries-old academic convention that obviously predates rock musicians maintains that a pair of strings is termed a course and instruments with courses are named for their number of COURSES. You "convention" you mention that contradicts this is nothing more than ignorance you wish to dress up as something more. 

Tell me, Andrew Alder (church drummer and rhythm guitarist who has never in his life played an actual "ten-string guitar"), if you notate music for a coursed instrument, do you write 12 or 10 separate lines in tablature? NO. You write one per course, which is in practical musical effect one string. If you write it in musical notation (can you even read this??? I doubt highly), would you use numbered circles up to 10 or 12 for each so-called individual string? NO! You would notate the first two strings as a circled number 1, the second pair of strigns as a circled 2, the 5th and 6th strings as a circled number 3, etc. These instruments are COURSED! For all practical purposes these instruments are NOT "ten-string guitars" (with the hypen) a term that has come to signify a specific instrument, an instument you are obscuring and confusing by introducing misinformative garbage. You deserve no less than uncivility. I wil let you play at being a musicologist for a few weeks/months until I have the time to undo your work. So play ahead.129.94.133.166