I have been testing these two 4x5 films for awhile with various developers, both semi stand with Pyrocat, and continuous agitation with HC110. My staple for years was Trix (the old 400) with HC110. I am testing Trix 320 and FP4 with Pyrocat HD and MC in tubes, as well as HC110 in the tray as the standard.
One thing I seem to notice (no controlled data, just a trend) is that the FP4 seems to be more sensitive to agitation patterns, whether in tubes, or even continuous tray agitation. (When doing continuous tray, I rotate the pile 90 degrees CW every minute, emulsion is up, going from bottom to top.)

Tube runs get 5 min presoak, tray runs get 2 min presoak.

Years ago I used FP4 (like, in the 70s) with ID11, continuous, no problems). Also, for what it's worth, it is an 8x10 tray, with 1000cc developer, water stop, TF4 fixer.

Anyone else have this experience with FP4?