Ian Leake uses HP5 at 800 in Rodinal for his high key platinum prints (I believe) so it's doable. FP4 in Pyrocat-HD at 80 for me makes it quite difficult to use in 7x17. Throw in a filter and the problems are greater. These beasts are big and very wind affected. My plan is to try some Max-Pyro and hopefully use HP5 at 400, which would make a big difference. Can always use an ND filter if your shutter speeds are not fast enough. All that said, I've not tried any Pt/Pd prints with HP5 in PyroHD.
Anyone now where Lodima fits in the CI scale compared to Silver and Alt prints such as Pt or Pd?