Is 1/2" leaf spring relocation worth the trouble?

If you are putting the B rear under the car WITHOUT relocating the perches then I would say it would be best to relocate the spring mounts to match the rear perch width.

If you are worried about the extra width of the B axel, wheels with a different Backspace can solve that.

If you have specific wheels and they need an additional inward spacing of the spring to fit, then you have to move the spring or space the wheel out if you can