This is my setup. The pics are from older RR ladder where I used a non-sewn prusik, which has worked fine with proper knots. The easiest option has been a sewn prusik that I've found from Sterling Rope with 13 inch loop end-to-end. The hardware can be bought on-line, but essentially a stainless steel bushing with bolt passing through it with washers on both sides of the ladder attachment points. Some may prefer to have washer on terminal end of bushing or stud, but I've found it harder to attach the prusik loop and unnecessary. Even if inadvertently knocked loose the prusik loop has never slipped off the stud. Under tension, you cannot pull the prusik loop from the stud.
As for using RR ladders for one-sticking, I've not tried them or any other method of one-sticking.