In reply to BernNolan:
I'm also left handed and currently use a GriGri2 as my sport belay device.
I belay left handed as a rule but can if need be swap to right handed if the situation dictates. Petzl have issued some left handed best practice guidance which is not an easy as belaying right handed imo.
When it comes to lowering on the GriGri2 I immediately switch to right handed which is completely natural thing to do as you also need to operate the brake lever to control the descent and this will be in your left hand.
See if you can borrow one at your local wall and see if it works for you?