I second ClydeFrog's recommendation for you to check out Milt Sparks holsters. All my carry guns are carried in Sparks holsters.
Before you look any further at the Serpa holsters. I recommend you do a search on issues and problems people have had with them. The issues have even had the Serpa holster banned at FLETC. I also believe in IDPA competition. I am not involved with IDPA but there were a few hits on IDPA banning the holster.