I recognize that thread.
What you want to make sure of is that the width where the joint replaced the existing bushing is the same. Otherwise you will need to use a washer or a similar device to act as a shim to make up the difference. If you do it right you will have the same length as before, just with a beefy new joint.
The rig you want to look at for whitfield's Tracker. I'm pretty sure his is the one where I saw the modifications done to the stock arms to lengthen them a bit, as it's the only reference I can find on the site. But almost all his pictures are dead.
I lengthened my arms 5/8" and shifted the ball joint forward 5/8" as well. I replaced the stock bushings with Energy Suspension ones. The center sleve fits a 5/8" bolt so I just drilled out the front mounts that are factory 9/16". The OD of the ES bushings was perfect for the 9/16" side but the other was larger. I had some 1.75" OD .125" wall tubing that it fit inside of perfect so I welded a section of it into the stock arm then the ES bushings fit great. A quick coat of paint and it was done.
I need to still get some 5/8" washers like said tho. I put the arms in as is and it crushed the factory brackets in slightly. I'll probably only do 1 per side as that's all that was needed. I know I should have taken pics but yea.