Low level (1000 FT AGL), VFR for accurate nav all info on the map .No plog required.
Triangle as you say for Track (M). Marks on map at every minute at required Ground speed. Required ETA in Mins and secs written on at each Turning point. All nav by look out and map. No Heading needed to be pre-calculated. If drifting a couple of hundred yards of track adjust to follow track exactly. Adjust speed to keep to minute marks and hence required ETA.
As video originally by RAF ; now used in Precision and Rally Flying Competitions every week througout Europe.
Not difficult and a sociable way of improving accurate flying.
http://www.precisionflying.co.uk/
Have fun
Overandout