I know that some of you guys shoot IDPA, and may have an answer for me. I'm looking for a decent "fast" holster (no thumb break or release button) to use in IPSC shooting. I nearly ordered the DeSantis Speed Scabbard, but I'm not sure if the M&P model allows you to carry with the barrel nearly vertical. To complicate things a bit, I'm a lefty. The IPSC rules aren't too harsh regarding holsters, but I obviously need to fit within them. Anybody got a recommendation?