Welcome Click!
I have a PM40 and have not noticed it having a aggressive texture to the grip so I may not be the best one to answer this question eithor, but...
I think once you do find a Rohrbaugh to get your hand around you will find it to fit like a glove (that is for a 9mm pocket pistol anyway). I own and have carried lots of pocket pistols and find that the Rohrbaugh or a Seecamp 380 (or many times both) almost always find there way into my pocket. I can't remember when I had my PM40, P3at, P32, Guardian, G26, NAA mini (I do carry a black widow on my ankle daily) or my snubby's in my pocket last.
I am 6'1" with avg. hands and have Zero problems with gripping the R9. Try to find one to see for yourself, we (forum members) are all over and you may find someone local to you that would let you shoot one. I think you will like it!