Cragar wheels

[8835th]

Hi, I am a new member and have just purchased a 1973 Plum AMX. The car currently has a Centerline type wheel but I'd like to change them to a Cragar SS wheel. Can anyone advise of backspace needed for a 15x8 rim, front and rear? Also will a 15x7 fit on the front with disk brakes without a spacer? Lastly, does anyone know the size of the lug nuts (1/2 or 7/16 thread size?) Thankx in advance for any recommendations. Tom