Not a great deal to worry about imo.
I would lengthen my hangars and put the axle in the position it was.
Either lengthen the short hangar or get longer ones.
I have a pair of F body ss hangars that are really long.
just a matter of drilling the spring eye holes where you want.
Possible to weld a 3 inch pc of plate on the hanger and redrill new location?
some pics would help.
Ideally if you have NO issues, that 1 and a half inches would be ideal as it ultimatly puts more wght on the real axle.
I personallly dont like locating on anything but the center of the spring.
for your info, there are products available that adjust that dimension so I cant say it wont be ok, I just dont care to set up suspension that way.
unfamiliar with b body hangars and there configuration.