Hey Vic, I'd say there is no "proper" sitting position, aside from bone-on-bone, as you mentioned. If I wer flexible to put my knees to the ground I sure would. Put your elbows on the inside of your knees, as explained, and demostrated in Figure three. You might not be able to tell, because of the shooting jacket, but my elbows are actually in front of my knees, and resting on my shins. It makes for a very stable position. I can see how the picture could cause confusion. Get into the position of your choice and try to place your elbows on the ground. That's the idea. They will probably be on your shins, unless you are very flexible (they'll be on the ground), or have limited flexibility, a large belly, or both, in which case they will be much higher. Unless they are on top of the knee, it should be adequate. Again, the lower the elbow, the tighter the position.
This is the law:
There is no possible victory in defense,
The sword is more important than the shield,
And skill is more important than either,
The final weapon is the brain.
All else is supplemental.
- John Steinbeck