The disc I got had the structure for the top link cut off. When I made new I copied the height from my back blade. Turns out the attachment point was too high to really get the rear gang into the soil with the top link I had.
The easy answer was obviously to get a longer top link, but I had no luck finding a longer cat 0 link.
So it occurred to me another solution would be an extension for the existing top link. I fabbed up a 3" extension from some 3/4NC all thread and a coupler.
I tacked the all thread inside the coupler with the stick welder to keep it from unscrewing.