Auto-X / Roadrace rear suspension 1969 Valiant

Have you had a look at the Control Freak parallel 4-link with panhard bar?
4-Link MOPAR Coil-Over Rear Suspension Systems | Control Freak Suspensions
I bought one because I like the adjustability without the binding of the triangulated upper arms. However I haven’t fitted it yet, so it’s all just theoretical at this point.