This problem is just basically a hugh dyno. Start on the [sloping] shelf all the way left on the main east face. Dyno to the lip and then mantle over. It is a scary top out. Either go all the way to the top of the Plethora or descend the south face.
Protection
The top out on this problem is awkward and sketch. A couple pads and spotters are nice. Fortunatley the landing in level.
Yeah, that undercling has been very aggressively "cleaned out" over the last couple years it seems. In fact, previously it was easier to just ignore the undercling and dyno from the slopers (like the above description states). This is probably why the problem felt quite a bit easier (in fact I think it is about V3 with the undercling and a static move). However, you can still preserve the original problem and just ignore the undercling and jump from the rail.