I use the stock Traxxas posts, I put a M4X12 mm set screw in them with red Locktite then use a lock nut to secure the rocker. I was tired of trying to unscrew that M4 button head screw and the post would come with it. I got the idea from Lunsdford titanium posts. They are machine with a threaded post on top for a nut instead of a threaded hole for a screw.
So you break your last set of rear P2 rockers and you are still waiting for the new sets to come in. What do you do? Leave the truck on the table and wait? I say no way! Take your unused Long Travel rockers, make P2 rockers out of them and keep on bashing or racing.
Putting the broken P2 rocker on top, it might not be absolutely perfect but I would say it's pretty darn close. All the holes line up very nicely.