When I started to read your post, I decided to take the red pill, as I believe GM did a great job engineering these trucks, but also feel there is a ton of improvement in many areas of these trucks.
Now after reading your post I wanna go back and take the blue pill. Common sense tells me that with the upper ball joint flange on top of the upper control arm and those four small bolts (5/16" maybe?) decide to break (due to the stress that is on them from the torsion bar trying to pry the spindle from the ball joint - supporting the weight of such a heavy vehicle), the flange will keep the upper ball joint and control arm from completely separating. Now with your setup, you can only rely on the four small bolts to keep this setup together when rolling down the highway. When these four small bolts decide they don't want to hold this all together anymore, one can probably guess a major accident will occur. Now if this truck spends any time off road and the suspension is at max articulation, I can guaruntee the forces involved will try to break theose small bolts.
I applaud your efforts for trying to fix an issue in these trucks, but I'll rely on the millions of dollars of engineering money that went into having the flange on top of the control arm. Basic knowledge of the laws of physics has made my decision.
