DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?

Interesting that you run an extended UBJ. I thought about lengthening the top of my fabricated spindle as part of the project but figured the initial pass would use the stock geometry and I would look at that aspect afterwards. Sounds like a worthwhile direction if the project ever comes to fruition.
While the taller spindle package raises roll center, it shortens the moment arm. This reduces body roll. It’s a neat way to reduce roll couple while achieving good handling and maintaining ride quality. Look at how tall OE spindles are on front suspensions that use typical double A arms.