offset bushings will bind though, how can they not, i think your confusing rubber compliance with zero binding.
as i said, change the rubber for anything harder and you have to have the bolts perfectly aligned. don't forget the bolts when adjusted stay in parallel with the chassis whereas the arm doesn't. Spherical joints would be the only way for zero binding with extreme adjustments.
but i'm also curios how cutting out the top arm mounts 'easily' and accurately then welding them back in 'easily' and accurately is actually easier than welding four holes shut and redrilling them in different positions?