So back to the original question, how do changes in distance change the bodies posture/structure. I think the answer is so simple it is very difficult. As the distances change, find comfort/harmony within yourself and with those changes and work from there. Discomfort creates physical tension which the attacker can and will utilize against you. Discomfort creates phyiscal tension which makes it difficult to move properly. Discomfort creates mental/emotional tension which limits the ability to see opportunities to escape, move or counter attack.
Training the foundation makes everything else much, much easier.
You have a very interesting and inspiring point and I agree- thanks for sharing.