http://soaringcafe.com/2011/09/flying-tats-with-clearnav/

When you start using large cylinders for TP's pilots will start
wanting their instruments to assist them. Software updates to instruments may be
a barrier to use large TP cylinders, particularly for O&R and triangle tasks.
Personally I like the use of 'speed' as the major variable for task scoring.
This article illustrates how one flight computer works.

Thanks to Ron Gleason