I only use pyrocat in a Unidrum (not hangers), and I haven't tried it with HP5, but Clay's recommendations seem on par with my times for FP4+. I've found development times aren't super critical, though. By the way, are these negs intended for alternative process (which will need more contrast)?

As to fixer, I've only used Kodak Rapid, without the hardener added. So I guess I can't help you there.

Also, with pyro and pyrocatechin developers, be sure to make a print before judging the quality of the negative, because the stain can give different result from what you expect. PyrocatHD won't give much of a stain when compared to say, PMK, but there is a stain nonetheless. Just compare it to a regular negative and you'll see it.