Got Baroness today. I have to say this is the first female figure I've gotten that I've really liked and felt was done really well. The body is great and the headsculpts and paint are wonderful too. The only problem is I feel she is incomplete. She has a spot for two spare magazines for the Uzi, but only comes with one spare. Then she has the pistol holster on her left thigh and doesn't come with a pistol for it. WTF? Its worse than when Beachhead didn't come with enough mags to fill up his vest. I mean a missing sidearm is a huge oversight IMO. And at her price that shouldn't have happened. As a figure I'd say she is better than CC, but as a complete package, I didn't feel CC was incomplete (some would argue him missing his laser pistol) - all of his holsters get filled at least. So overall they basically tie because of their own faults.
the holster is for the uzi, you're supposed to take both clips out and put them in the pouches, that's why there are two.
Believe me, I had to just try to put the uzi in the holster to answer your exact questions. When I saw how snug it went in the holster there was my answer.
I also suggest leave one clip in the uzi, don't worry the holster holds it fine, reason is the mags fight really tight in the pouches. It's a pain to remove them.