I've been using the same Ted Blocker holster since the late 80s (LFI rig-IWB 5") and it's only let the safety come off 2 or three times in all that time. Every time was during periods of high activity.
I dunno if Ted Blocker is still around. His holsters rock. Prolly any good holster (read $75 and up) will be good for you.
Here's the pic of mine in another thread.