First off let me say, I'm new to this 22 LR game and know nothing and I'm learning every day.Wow. If you think anyone can win in SB prone competition with "less than RFBR accuracy", you may want to venture outside your discipline.
Shilen barrels are great, but to the OP Benchmark barrels are also equally good. Unfortunately, its the luck of the draw though. These manufacturers tend to put the odds in your favor though!
kev
Shilen and Benchmark were the two barrels I was looking at when I got my rifle. At the time I couldn't get the Benchmark at the length I wanted so went with the Shilen. I've heard good thing about Benchmark.