Input on Slick size for 72 Swinger

I put the Dr. Diff offset spring hanger kit in my car. 002/003 Super Stock springs, 15"x7" stock steel wheels with 4.25" BS. I got 28"x9" M/T ET Drags to fit perfect. 1" between the sidewall and the spring, 1/2" between sidewall and the wheel lip. BTW, my car is a '70 Swinger.