I never cared for Uncle Mikes holsters, I had one briefly for my .45 APC and hated it. I consider them a rag in the making. If I was carrying a gun as large as the OP's I would want a leather holster which is a lot more substantial and will last forever if cared for. If the leather holster recommended won't work you can always have a custom made holster made.
When you are up to your butt in alligators, it is hard to remember your intent was to drain the swamp. Stay focused!