3 link ?

[Bryce]

Upper link is typically not parrallel to the LCAs. There are suspension caluclators out there to determine you anti-squat, roll center, and roll axis angle. All of those are important to determine the handling characteristics of your car. Just welding on a third bar is the easy part. Plu syou need to figure out how much adjustment you want. How close can the mounting holes be so make adjustments, how does each hole change your geometry.

Sounds like a cool idea, just need to determine the geometry.