When I want to shoot 4x5" handheld, I usually use Tri-X in Acufine at EI 640. If you like HP5, you'll probably be able to get a little more speed with it than Tri-X in Acufine, Diafine, or Microphen.

Grafmatics are great, especially for portraits. I've got 8 so I can always have a few loaded with different kinds of film (lately Tri-X, Efke PL100, and Astia) and a few empty and ready to load.