Jesus, there are 2 trophies to be won, one for best fuel efficiency and the other for best thrust/weight ratio. Engines have to be run at the same rpm for 2 mins minimum, so once the engine is settled at the selected rpm and the operator is happy the run is timed with measurements of fuel used and thrust taken.

If a particular engine has it's max efficiency point less than max thrust then 2 runs would be required at the appropriate rpm points.

Hope thats clearer.

Rob.