Go to a match and ask questions. See if anyone has a used rifle for sale. If you get hooked you’ll eventually have a rifle built and probably end up with a one piece rest but right now you don’t know what will work for you. You need to shoot awhile. Just go to a match most everyone there will be willing to help. You can also get in contact with the local match directors and they can help you out immensely. Most people buy a custom built rifle, one piece rest, and flags, then go to a match and find out they are either not able to devote the time to do lot testing or the money. That is the hardest part of rimfire bench rest. The people that do get hooked get hooked hard and test ammo on a constant basis. It’s a great shooting sport but it takes the right type of person that loves to test constantly. Many a great shooting rifle have never been realized because the owner hasn’t found the right lot of ammo that will compete in that gun.