Wow. I spent my earliest years in the SF Bay Area, and remember going to summer camp at "Camp Chabot" when I was 9 or 10.... many years ago.
While the IDPA Little Green Book (Rule Book) makes a fetish out of "approved" holsters, I've never heard of a brand name holster that wasn't designed for IPSC, and which covered the trigger area, being disqualified at an IDPA match.
If you use only the Big-Name approved holsters, you'll tie up a lot of BIG-dollars in the process. I'd recommend you be a little more frugal up front, and get a good Kydex holster. ($30 range). Then, as you shoot and come to better understand what you like and need, then spring for a more expensive version.