Out with SS springs and in with?????

I'm also getting springs soon. I got the local spring shop Hemi 6 leafs on the other '67. Yes still stiff now, made in '85. How much are the ESPO's and are they just stock replacements ? Would you get those or Hodgkiss. They claim more progress spring rate. I know leafs are inherintly progessive rate.
Was going to get the full caltrac setup, but thinking of that with Hodgkiss springs. '67 f/b 440, 727. Any help/suggestions, only want to do this once, thanks C300