The man wants MORE caster. How about this idea?

All good info, just to throw this out there, do a 180 and look at the lower ball joint if the holes to bolt to the spindle were drilled in a different location causing the lower portion of the spindle forward say 1/4-inch wont that help with positive caster, maybe someone can make this happen and should not cost much more during manufacturing replacement parts. What do you think.

I think the spindles are symmetric, and it's really unlikely the mounting holes for the steering arms are off a 1/4" on a machined part since the tolerances for that stuff is in thousandths.