I like the recommendation to start with arms straight down from shoulders with 90-100 degrees or so for the front leg (but not leaning too far forward) and then adjust from there. Worse case scenario it keeps them from falling on their faces and being in a good position after 10m or so.
This is one of my primary benchmarks. It ensures stability in the set position which is requisite for maximal force application.
ELITETRACK Founder