Run your Jobo at the slowest possible setting, below the F(or P, whatever that first letter on the rotation speed dial is), just before it turns off. Then you can use the normal development times for whatever developer you're using. Even if they come out a bit contrasty, you can always print with a Grade 1 or Grade 0 filter using VC paper. HP5+ is not as responsive to expansion/contraction development as other films, even FP4+, so you can overcook it a bit without being too worried about the highlights getting blown out.