If you know the mechanics and are clear ready, then it's not really a fight difficulty issue. You won't clear if you're consistently playing with people behind your progression point. Either get a group of friends together and clear it, or be upfront and strict about your goals in PF and make revisions to your group as needed.

All PF content is paradoxically easier the earlier that you do it (i.e. the first couple of days will generally have you be done in a couple of lockouts.) If you want to be time efficient, it's always easier to invest your time in upfront than later on, especially when there's no 'gearing' to be had. Try this with the 6.5 Extreme when it gets released. You'll be amazed at how much easier it is.