The '66-67 reproduction wire wheels are offset differently:
backspacing - front 3 1/2"
- rear 4".
Depending on tire size used, the clearance with the 6" wide rim is the same as with the 5". In theory, the skirts should fit, with a stock size tire. Each car varies a bit, so test fitting is best.
Tire rotation becomes more complicated, requiring dismounting, mounting and re-balancing each time due to the different offsets.
I run 4 15X7" w/3 1/2" backspace steel wheels with 225 60R 15 WSW tires with out skirts on my '57.