What's the best way to attack the Philly Defense?

What's the best way of attacking the Philly defense (horizontal lead arm, windshield wiper rear arm) in the pocket? (Maybe now it's called "the Mayweather")

I've seen the following attacks work. Attack the lead ribs behind the elbow, come over the top (to the temple) on the same side and follow up with an upper cut is a combination that I have seen work. In our gym, we have also had some success pinning the rear arm to the opponents own body (to his side, hopefully across his face) and then landing a left hook. I am open to other ideas or anyone that wants to disagree with mine.

I like to condition opponent to the straight cross then throw an overhand right (turning it over at the last min)
also feinting right body shot and coming up with a right hook to the head. Also feinting the jab and throwing a slappy left hood at the last second sometimes works.
hope at least one of those works for you

It makes sense when you say you had success with the lead ribs. The punches you want to avoid are hooks to the rear ribs cos it brings you too into deep to be countered with the right hand. Basically they are looking to counter with a rear straight or lead hook. I don't know about the best way but the safest way is to attack the lead side of his body/head and move/slip/roll to the outside of his lead hand afterwards. Don't overcommit and pick him off with the jab and use convincing feints. I may be wrong but the philly shell user is waiting for you to lead so he can time this and answer with his own counter. Why give him that? Try to feint him into leading himself and hit him as he is coming to you as in that moment he won't be in a defensive philly shell.