Let's start with the barrel question. After some initial testing I would have been willing to bet money that the 20" Hammerhead from Carmatech was going outperform my 14" Hammerhead Mojo. I tested both of those barrels (along with Others) extensively. Bill and I shot them inside while the gun was mounted to a Lead Sled. The 20" Hammerhead tested just fine but the 14" Hammerhead was better. A lot better. Not to mention you don't have to contend with the extra barrel length and weight.
I still believe that when it comes to the SR1 that the 14" Hammerhead barrels are really hard to beat.