First priority is get your family out of harms way then assess the situation. My 2 cents...if people are dying you must engage. That's why I'm at the gun club weekly practicing drills on silhouettes.
I don't really like a thumbreak. I usually carry in Condition 3 so to me it's just another complexity added to the draw. When I carry a 1911 it's normally with a Galco Avenger owb holster without thumbreak.
Some of our local shops in Scottsdale have S&B in 9mm for $7.50 and only slightly more for 40 & 45 cal. So by the time you pay for shipping it's hard to justify buying small quantities of ammo over the internet.
I have an RIA 1911 in 9mm and it normally runs great. Having said that, it does not like certain types of ammo. I have had nothing but problems with Winchester 9mm 124 Gr Nato rounds...stove piping, failure to feed, etc. Yet with Federal American Eagle 9mm in 115 Gr it cycles perfectly. So...