Alignment Woes
By the pix, it would appear that the cams are all pretty much "centered" in their adjustment.
I believe there should be ample movement to add additional Caster, to gain more directional stability.
We're it mine, with correctly installed offset bushings (K7103), I would expect to be able to achieve almost 3*+ caster with the cams cranked properly, frame straight.
This chart is what we now set the new radial tires.
The factory specs ( 0* to -1 1/4*) are for bias ply tires,.
Good luck
jmo