Disc Brake swap What wheels?

I'm converting to disc brakes on 66 Barracuda using 75 dart slider disc setup. What size rims and tires did you use? Looking to replace present 195/70/14 with larger tires that will fit the new setup. I have 15"/5.5 Ralley, 14"/6.0 Ralley and American Racing Outlaw 15"/7 available. Trying to decide what size rim and tire to go with.
Thanks