More needed caster?
There’s really no reason to be cutting and welding on a factory UCA. Pretty much all of the aftermarket tubular UCA’s have several additional degrees of caster already built in. QA1, Firm Feel, PST, Hotchkis, etc.
And then there’s the SPC double adjustable UCA’s @BergmanAutoCraft
BAC/SPC 1.0 UPPER CONTROL ARM - Bergman Auto Craft
Fully adjustable on the car, no need to remove the UCA to make adjustments beyond the scope of the caster bolts. I run them on my Duster and had no issue getting +6.5° of caster with plenty of adjustment left over.
Another thing to consider is the shape of the UCA does matter, especially if you run wide front rims. The wider “U” shaped arms can interfere with a 9” front rim, where those with a “V” shape clear fine.