Early A body rear end narrow questions

Gents,
Did a pretty good search of the archives but couldn't find my answer(s). I'm about to narrow a c-body 8 & 3/4 for my '64 barracuda. The car has not been minitubbed and I don't plan on it but do want to maximize the tire width. Few questions:

1. Do I gain any room by using the offset shackles and front hanger brackets? pn 4120077 & 4120075. Seems to me like the inner wheelhousing still gets in the way on the early a-bodies. Seems like some debate in the different forums on this.

2. If I go with the offset shackles and brackets, what is the new perch to perch width? Stock is 43". As far as I can tell the perches would need to be moved in .8" per side.

3. Width to cut the rear to will be a separate post.....

Mark
'64 Barracuda