I could sure use some help figuring out how to get this working nicely. Here's the list of things that I am trying to fix right now:
1) Flight stability - adjusted, but it's far from right. Adjusting is not straight forward, so finding the sweetspot or magic combination is elusive.
2) Wheel suspension - Animations are fixed, but the physical handling is way off.
3) Folding wingtips, F/A-18 style FIXED
4) remove co-pilot FIXED

AirplaneX vs Geom LOD
After spending several hours messing with "draconic forces" and planar surface values in the config, my airplane is still acting weird. Currently, it requires 232kph to take off, whereas I'd prefer it to be about 80mph (~129kph). Once it takes off, there is little forgiveness in pitch changes before it starts to bob up and down violently, but with very subtle changes it can do a steady climb. It's like the config parameters are fighting with the plane's shape. I've started the config from the NATO UAV, which shares a similar wing layout (forward canard style elevators), but I must be overlooking something, I think. How much does the actual shape of the Geometry LOD and GeomPhys LOD affect its flight? Here is a printscreen of its GEOM LOD in OB.

Fig. 1: Firebat/Hellwing Geom_LOD in Object builder.
config.cpp (updated):
Wheels & Suspension
Notice in the image above that the front wheel doesn't droop as far as the main/rear wheels do. It is intended to have a nose down stance while on the ground, but I aligned it to its flight path (Z axis) in OB. I'm not sure if that's the correct way to do it; I just assumed its weight distribution and suspension settings would make it rest properly on ground. Something weird was also happening: Addon Breaker was compiling my PBO, even though it had some syntax errors. During that time, the wheels were aligned to the ground and working fine. The truly weird part: after I found and corrected the missing semi-colons (located after the map icon .paa line), the wheel behavior became wonky as you see in the images below. In short, the jacked up syntax version made the suspension and wheels work better. Huh.
  This is what the wheels look like when the plane is freshly loaded into the arsenal/garage:

Fig. 2: Fresh spawn
...and after starting the engine and moving forward a few feet, the rear wheels are a little less sunken while the front wheel is still raised:
Fig. 3: Allowing the wheel physics to readjust/kick in  
Fig. 4: After getting out and looking at it from prone, the wheels are sunken again.

Some information about the plane:
This is based on two planes - the real life BD5J and the fictional Cobra Firebat. It's a small, light weight, short-range bomber/fighter with very limited avionic technology. It has a wide gliding surface and canard-style elevators. The wings are supposed to fold upwards for storage (but that isn't working either) and vertical catapult launching (from e.g. a missile silo) , and it barely has room for one pilot.

As always, any help is much appreciated!

EDIT:
here is also the model.cfg (updated):
 
Edit 2: I am realizing to my horror how messed up my model.cfg is, with redundant selections and obsolete min/maxValue settings for dampers. My corrections so far have allowed the wheels to rest on the ground, yet the suspension is still really stiff. I have to hard dive into the ground in order to notice any change.

Edit 3: Docs are updated, and some fixes were noted. Problems still persist.