This is a view of the whole Backstay Adjuster. I normally keep the Backstay very loose. Just tight enough to keep the adjuster from falling down too far from gravity.

Backstay

This view shows the approximately two inch D shackles that replace the stock pins on each side.

D Shackle

Note that the turnbuckles are backed most of the way out to give a loose backstay at rest.

Another shackle view.

This is the lower fiddle block with cam and becket. I used Schaefer 7 series blocks. This makes a four part tackle. But the wire almost doubles the purchase. If I had to do it again, I might look at some smaller blocks, although this setup is bullet proof and works very well.

Lower Block

A photo of the upper fiddle block and Johnson Marine adjuster. Note the 7 X 19 wire that runs from the starboard side, up through the adjuster and down to the upper block. I think its at least 1/4 in diameter. I used oval sleeves, Stainless thimbles, and a Seafit hand swager to make up the Wire.
This setup is kind of overkill. It almost seems like I could pull the mast down!

Upper view