Massive caster variance Side to side

I like how you think, but that would be a less desirable solution than using the UCAs with adjustable and/or built in additional caster which already exist in many forms. The load would be moved further out on the pin, increasing the force required by the pin to carry. It's been over 40 years since I took statics and dynamics, so I don't remember how to calculate the additional force, but I'm sure one of our engineers on the forum could. Maybe not a problem, maybe not. I think it might also require adjustable strut rods, or at least a custom bushing. It would also likely cause an issue with the torsion bar seating properly.
force would be the same, but increasing the cantilever increases the moment in the out of axis direction. 1/4" probably isn't that big of a deal, and there's enough play fore-aft in the t-bar socket for it to be OK. bigger issue is there is only so much room for it to go foreward, and it's not ideal if you're pulling the outboard side of the LCA so far forward that it is no longer naturally perpendicular to the pivot pin.