I am dropping off my CZ 455 Precision Trainer at Benchmark to have it threaded for my Sparrow. I originally plaaned on cutting it to 16" since probably over 50% of my shooting will be supressed. However, I am worried that a short barrel with the long forearm will be odd. Should I leave it at 20" or find a happy medium at 18"? Rifle will be used primarily for prone target shooting. Any Advice? Any pics? Thanks for the help.