Like you, I feel the grip texture is a tad rough. After about 100 rounds, my hand can get a bit red.
I tried purchasing a 1.0 backstrap, but they aren't interchangeable. A fellow member suggested sanding it down lightly with a dremel. I am no expert so I decided against it. Instead I purchased Talon grips. I will say that I love the way they feel, however, the pointy edges sometimes pull out. You can cut them and it will take care of that issue.
I don't know about mailing the plastic portion of the handgun, but as it is the serialized part, I am thinking that it requires an FFL. I know if you are just sending the slide, there is not requirement there.
I continue to use the Talon grips which I am happy with, but according to the manufacturer, they are good for ~1 year.
Good luck.
CH