The man wants MORE caster. How about this idea?

Building super stocks and super modifiers, we were limited by rule to using stock control arms, but made no mention of "altered".
We were using Camaro clips, and butchered the control arms something fierce, then crashed em, not by choice, to "test" it.
Chop and weld away, all's good.
Cadillac had an interesting upper ball joints.
I used to bend the outer end of the lower control arm, then weld in the supports to "box" the control arm .
Using Moog offset bushes, I wasn't able to achieve more than 3*
caster, and most customers bitched about heavy steering at 3.
I usually set them up at 2 1/2 max, especially with manual steering.
There is also a fatigue issue some folks might have cranking the wheel .
Anyone given thought to what happens to toe when caster is way up?

Toe changes depends on a lot of things. Changing the caster would have a small effect, but so does lowering the car and a bunch of other things.

I run +6.5° of caster on my Duster and haven't noticed any bump steer. I did notice it when I was running 2" drop spindles on my Challenger.
Wouldn't the ball joint have to be relocated, not just the angle changed? With the proper fixtures though, your proposed process would be relatively easy and have minimal knock-on effects. Fewer risks too since the integrity of the arms is retained.

Crap, you're absolutely right. Not enough coffee this morning. Changing the angle on a ball joint wouldn't do it. You'd have to slide the whole ball joint toward the rear of the car to increase the caster.