There are several .45 cal magazine pouches on the open market that might prove highly suitable for you. My Bianchi is vertical only but holds a Leatherman and a Buck 110. I have to put a little bit of paper towel into the bottom of the pouch that the Leatherman resides in.
These pouches are now being made for vertical and horizontal use and the snaps have more than sufficient tension to stay snapped.
These pouches will also make some people wonder what you're carrying & that can be both good and bad.