couple of wheel questions for 2.5" drop spindle/disc brakes

[69Tom]

Hey guys. Have a couple questions. I'm getting some 2.5" drop spindles for my '70. I will be running 71-72 disc brake calipers. I want to make sure I don't get wheels that are either too wide or not enough back space for the front. Going to be running some Wheel Vintiques Steel Wheels (http://www.summitracing.com/parts/wvi-62-5834044)

1) Are 15 x 8 too wide for the front with the 2.5" drop spindle? I know that most guys run a 15 x 7 up front, which I have no issue doing. Just want to make sure I get the correct ones off the bat.

2) I think it should be ok, but is the 4.25" backspace enough for clearance with the disc set up?

I appreciate the help.

Tom