Well, your Oranguru would do a lot better with much more investment in defense. I use 164 while keeping Sassy and 92 points in SpD. It can tank physical hits much better and will be able to use Mental Herb more safely.
If there's one thing I've learned it's that 252 HP (with no other investment) is almost never ideal for most pokes, especially when there are certain attacks you want to keep under a specific threshhold.
Leading with a weakness shared by the setter isn't too much of a gamble until both are OHKOd by the same move; having to make that coin flip is an uncomfortable position to be in. Marowak is targeted mostly because it can be killed by the things that Oranguru can survive, if only barely.
Sitrus Berries are a thing of the past. The pinch berries that cause confusion if disliked were majorly buffed and now restore 50%. Use the one with dry flavor, which Quiet pokes prefer eating. Having said that, I think Wishiwashi's physical set is more accommodating and still allows use of Ice Beam for heavy damage on certain targets. Because it's so slow and its HP is so crappy, you may find Endeavor more useful than HP Grass. Your set looks incredibly weak given its otherwise enormous SpA.
I'm a big fan of Mudsdale and intend to try an Assault Vest variant myself, but otherwise have no experience with it. I wouldn't want to share a water weakness with two pokes, myself.
