Currently running a PHAT/Fortitude hybrid. There were aspects of each I did and didnt like.
Day1: Upper power + lower pump day (no failures)
Day2: Lower power + upper pump day (no failures)
Day3: Back hypertrophy (failure, rest-pause, drop sets etc)
Day4: Chest/arms hypertrophy (failure...)
Day5: Shoulders hypertrophy (failure...)
Day6: Legs hypertrophy (failure...)
Day7: Off
Can generally run it for 6-8 weeks before needing deload or switching to lower frequency protocol.