GREAT thread!
Only two thoughts:-
1.) The term 'hinge moment' may confuse some of us.
Try it this way: A moment is a force at an arm distance, tending to cause rotation about a point. When we move our control surfaces off neutral, they meet airloads trying to return them to neutral. A point where, in effect, all the airload acts on a surface can be SWAG'ed or estimated. The distance from that point to the hingeline is the moment arm, and the total force x that distance is the hinge moment.
To hold the control surfaces to angles needed to perform figures, we need to match the airload hinge moments, by shifting pull between the lines, sharing the full value of centrifugal force - split equally at neutral - to more on the 'loaded' line and less on the 'unloaded' line. The pull difference, led through the series of levers (bellcrank line radius, bellcrank pushrod radius, horn radii at each control surface) applies the matching counter moment.
The Netzeband Wall is hit when the pull (basically CF) cannot reach the values needed to hold or increase control surface deflection for conditions. The model does not turn tighter, however much we want it to. If too low, and it opens up... Next model please...
Note: It IS possible to add briefly to pull's CF value by yanking the handle away from the model. (Inertia permits a very brief boost to CF. Paul Walker, in a video I've seen, and in seeing him fly, uses this, quite violently, for corners. It does work!)
2.) Line curvature due to drag: (weight IS uniform, but very small and not sigificant for the following remarks.)
I've seen the curve our lines take in flight called an "accelerated catenary." A simple catenary is the curve we see in a cable suspension bridge, supported at both ends, for a cable of uniform weight load along its length. Our lines, in flight, do not meet a uniform load. Air drag varies with the square of velocity - which, itself, varies from (in effect) zero at the handle, to whatever value exists at the leadout guides.
Incidental to this: If the line pull direction, when it reaches the leadout guides, can be aimed at the CG, we gain. "Moments," again... LINE I and LINE II help for these concepts...
If the line pull aims ahead of the CG, it tends to pull the model's nose "in" toward the flier. And vice versa...
These are 'yaw' disturbances, and at extreme, can cause bad hinging. It is ideal when yaw and roll tendencies are at minimum.
Gyro effects from the propellor and crankshaft, for conventional (CCW rotation props, seen from in front,) ""nitro"" models (flown CCW), cause a nose-out tendency on inside turns, and, again, vice versa.
(It may be possible, if good numbers exist, to spread the leadout guides chordwise enough to reduce, or even counter, the yaw tendencies! For years, I've tried to cancel these for the worst case I could estimate, hoping that that would deal with "lesser included" conditions. I'm no rocket scientist -Howard and Brett are - but my approach seemed to work for my level of seriousness and potential...)
Over to you,Chet...