I am not clear on your thrust line use.
Some amphibian aircraft have engines much higher than the main wings.
The offset of the prop thrust line to the main wings will affect fuel
efficiency - the prop introduces more moment force pitching the
aircraft down and more elevator force is required to balance this -
thus more drag on the aircraft. Generally you will see canards engine
thrust line pretty close to the main wing
level - but usually higher to keep the prop clear of ground on
takeoff/landing.