I bought just the pouch on clearance a month back. It just didn't sit right on my kit. Sat right on top of my magazines in my front triple shingle, so I had to move the pouch to get to my magazines. I ended up taking it off, keeping those MOLLE loops slick, and putting a couple sharpies, extra gloves, and another TQ there. I toyed around with the idea of putting it on the back of a commando, but I figured Murphy would hit on that and said commando would be busy elsewhere when I need the pouch. I chose to adopt the fanny pack on my person and an "evac" bag in my ruck, and that system has worked well so far.
However, the pouch may work for you. I know another medic that put one on the outside of his M-9 bag. If you can't get your hands on one before you buy it, get the dimensions and make an educated guess.
Hope this helps.