Any Pertronix experts here?

Have a new Pertronix D141710 dist., need to buy the correct coil to use with it. I contacted Pertronix they state I can only use the 45111, .6omh unit, which a old style round type but when I read on web site , it states .6ohm or higher, I would like to run the 60115 unit, newer style estyle,which has 1.5 ohms , is it safe to use the one with 1.5ohms or follow the service rep. advice of the 45111 .6ohms, they same if I use the higher ohms both units will fail!

Dave