Help from the experts on 15x10 rear Challenger wheel fitment

[KillerBee]

OK
I just scored a set of  brand new 15x10 Torq Thrust II's for my 71 R/T Challenger.
The rims have 5 3/4".
I doubled checked, measured them, and ran the rim's part numbers and  the 5 3/4" back spacing is correct.
Now I need to get them stuffed under my Challenger.

Here are my options.
First I plan on using the offset spring hangers from Dr. Diff.
I have a of couple rear ends I can use.
First I can put my B body Dana 60 under the car
I know people who have done this and with DR. Diff's offset hangers they were able to use a 15x10 rim with a 5 1/2" backspacing, I'm not sure if my rim's 5 3/4" backspacing will fit but I could use 1/4"wheel spacers to more the rims out.

Second I could use my Challenger's stock E-body width 8 3/4 rear, again I would use Dr Diff's offset spring hangers and move and re-weld the spring pads inward on the E-body rear.
I think I've read that with the wider E-body rear end I can use a 10" rim with up to a 6" backspacing??

For the experts out there that have been there and done that which way would be the best?
I'm trying to fit the biggest tire under it I can, I'm hoping for a 315 50-15

Thanks.