GM A-body Currie Currectrac, which bushings?

[b-man]

I'm about to install some new Currie Currectrac rear control arms on my '64 Tempest.

There are no bushings supplied with these arms for the upper rear pivot points. What type of bushings should be installed in the upper rear end housing, rubber or poly?

Are rubber bushings necessary to prevent binding? If so, are there any harder durometer rubber bushings available or even advised for use for this application?

Any help or insight on this would be greatly appreciated.

Thanks, Bart