To Ward's #10
I hope my long note(Post #12) about the curve of the flying lines in flight makes sense. We don't really need the model to actually be yawed away from us! In more or less "normal" flight, the model will pull about 3g. So, a 1.5 lb model will pull 4.5 lb. It is best when the model's fuselage is at a tangent to the flight circle at the CG. Nose and tail aim very slightly outside the flight circle. The fuselage is straight - we hope - and the circle is round. Well duhh...
The term 'leadout rake' just means, that, at best, we have the leadout guides moved aft just enough so that when the curved line of force carried by the lines reaches the wingtip, that direction of pull force aims just about at the CG, If it aims too far forward, it will pull the nose in. Too far back, vice versa, it makes the yaw, relative to the air it the model flies through, excessive, costing speed and usually controllability as well.
Engine offset usually only wastes a small part of thrust. It may affect airflow around the fuselage. Propwash spirals as it moves aft. I use a small amount of offset. If all else is lost, the slight outward fraction of thrust might just get the model back out to the end of the lines before the ground gets to it.