I would also recommend the Glock 19 for production. It is a smaller frame glock so I would say add a grip to the magazine or something that might give you something to hold onto. Also, add a 3.5 pound connector to it. And most of all, worry about safety first then speed. I would say use the stuff you already have and if it becomes a regular thing for you then change your gear if it is necessary.
USPSA clubs are a very friendly helpful atmosphere. Try all of your guns. All the shooters will be happy to show what they use and explain why they use it. Just bring all your gear lots of ammo and have a blast. You will figure out what works best for you.
+1 on what mbtfarms said!! Bring your stuff and the good folks at these shoots will gladly show you what to do and what will work best for you. I went to 3 last year and had a blast! I will be going to more in 2012. Have fun, Terry.