It's a pretty good drawing actually.
My 2 Chargers have 275/60/15 w/ lots of room to spare on 8" rims, w/ approx. 4-4 1/2 backspace.
That is the sort of standard as I am sure you know.
I am always looking for 10" rims w/ the correct backspace (4 1/2- 5 1/2?).
Tires also seem to go up in price...
Here's my 2 cents, I have a 68 and a 70 Charger and added a 70 Super Bee recently. Non of my cars is perfect but they are all on the road and I like them all for different reasons. For now, I enjoy working on them and chasing parts, I like the hobby. If I ever need to sell I will but for now...
The 15 x 8" Torq Thrust were 4 1/2 backspace (I believe), sold them and bought 15 x 7" (which actually fit worse as they have less backspace)
The 66 Coronet rear wheel wells are tight, I can't see getting a 275/60/15 back there w/o modifying.
I run 275's on my Chargers w/ room to spare
My 2 cents, we have a 66 Coronet sedan and ran 255/60/15 Cooper Cobra on 8" Torque Thrust w/ 4.5" backspace, just a touch of rubbing occasionally on the passenger side (1/2 difference side to side).
Switched to 7" Torque Thrust w/ 235/70/15 BFG and it was worse because of less backspace on the...
I have a 68 and a 70 Charger and I can't decide which I like better, they are so different. The 68 is a survivor and the 70 was a parts car. I like driving the 70 and I am less afraid of it getting damaged. The 68 is cool because it hasn't been apart or messed with and lines are so crisp.