You're not going to get a fast film with tonal qualities similar to Pan F+, which these days is pretty unique. Pan F+ and HP5+ have distinct personalities which make them quite different from everything else (and each other -- they don't resemble each other at all). You might try Delta 100 in Rodinal, dilute XTOL, or Ilfosol S, all of which I think look better than DD-X, but that still won't get you the Pan F+ look. If it's the fine grain and contrast you like you might try TMX -- but that has its own unique look which you may or may not like. Just don't use TMax developer.