Here's my RR with the 265/50R15 fronts, 295/50R15 rears, all on same 15x8 Ramcharger steelies, 4.5 BS.
If I had it to do over again, I'd go with 60 series for more sidewall height; the 50s look a bit slim in side profile to me. Also, the 15x8s are a bit narrow for a 295 tire.
He's a bit of a workout when parallel parking, with that big-valve-cover lump in the nose and manual steering, if that matters, but I do like the way they fill up the width of the wheelwells.