I've been tinkering with this for a while, and today I hit on something that seemed to work very well in terms of how to anchor my machine to my trailer so that it's rock-solid and nothing gets scratched up or damaged by the chains.
I have an Anderson Manufacturing 18' equipment trailer rated for 10k. It has 16' of flat deck plus a 2' beavertail and fold-down ramps. There is one stake pocket behind the wheels and three in front of the wheels on each side. Here's how I tied down today.
Drive onto the trailer, bringing the machine up to a point where the rears are someone over the rear axle or slightly forward. Loader in the raised position with the bucket on. Drop the chain down through the middle stake pocket and pull the grab hook up and latch it on the front bumper bracket - do this on both sides. Once the chain is attached to the front bumper on each side, roll the tractor back to take up the slack in the chain.
Place the bucket in the full "dump" position and lower to the bed. Curl until it rests a few inches in front of the chain crossing the deck then rest on the deck. Drop the 3PH with ballast box into the full down position. Set the parking brake and leave the machine in gear.
Drop a hook through the rear stake pocket, bring it up on the outside and hook on the pocket. Do this on both sides. Lay the chain over the draw bar and catch the 2" ball that is attached there. Ratchet binder used to take up the slack here and make everything tight.
Second ratchet binder along the chain across the deck at the front to make everything very tight there. Heavy duty strap across the tops of the loader arms, using the stake pockets directly in front of the rear tires to anchor to.
Chains do not touch anything that can be scratched and the strap adds an additional layer of security for the loader and the bucket. Here are some pics.
Trailer pulled excellent - smooth, no sway, stopped nicely, no chattering. Machine never moved.