RE: simple questions...
All true. Work done is distance X force, and the servo has only so much power available, so spreading it over a greater distance reduces the force available.
If possible, I am all in favour of keeping it simple. If you dont ave room for a long enough arm, the doubling trick helps. Try to keep the anchor point at the end of the line as close as possible to, or at least in line with, the point where the line passes through the deck.