What did you go with for rear and gear choice ?

On the rear wheels, I want the center/hub of the wheel centered up in the wheel regardless of total width needed.

Why?
Do you want the wheel back spacing to be in the center of the wheel width exactly, IE 10 inch wide wheel with 5.0 back spacing?
Centered or negative offset makes them harder to put on and take off usually, the wider the wheels and tires the worst the problems
Been down that road more than once due to NHRA rules in NHRA stock classes years ago

That’s what I think too bc I believe it would be more stable but I do see these super narrow rear ends with super deep outside spacing but to me that doesn’t make sense.

High offset wheels benefit you by lightening the total weight of the rear end as an assembly in the car. If you have partial skirted wheel openings like a Dart, you really do not want long axles. Trying to get a big tire out with a high offset wheel is bad enough without adding to the drama. Wheel offset is of no concern with strength. All the fastest cars have the wheels offset. Heck, look at any vehicle with dual wheels. They are made for heavy loading.

I will always make the rear as narrow as I can, i.e.use the deepest offset wheel for the width I am using or may end up using. 1) Axles are shorter, less likely to twist or flex, likewise for the housing 2) Easier to get the wheels and tires on and off 3) The entire rear assembly is lighter. If I can save weight for the same money, I'm doing it.

If I'm fabricating spring mounts or suspension mounts using big tires, I will cheat the housing forward a bit 1) Weight distribution 2) If I need to trim the wheel opening, I only need to fool with the front of it.

I agree.

My rear end is moved back 1", it would be interesting to see how much the weight changes by moving the rear 1" either side of the factory location.

A factory A body 8.75 is 52 5/8"

The shorter number is from that garbage chart that is wrong. They are not 51.40"

AS mentioned measure to get it right with the wheel/tire package you want to run. You must have enough stick out beyond the leaf springs for a U bolt to grab before the housing end is in the way

That's why I said "I", it's just my preference. Assuming a 10" wide wheel with a 1" wide wheel center/hub, it would be 4.5" per side or wheel half. I don't size the rear end width or wheel stud length so I can't get the tires off in the first place, and don't mind if I need to let the rear end hang by using jack stands on the frame.

The roughly 1 lb. per axle saved making the rear end width 4" shorter isn't going show you much at all, because it's so close to center, there's more to be gained from the wheel itself and even better yet the tire. Some Pro Stock guys have a tire burn in car that's used to shave the tire OD's down, losing 4 lbs. at a 16"+ radius from center, now we're talking.

Fully aware of what's involved regarding NHRA Stock and Super Stock stuff, been there, done that, and doing that.