There's great info on the Lantus/Lev forums if you opt to go with one of them. For several of us that made the change for other reasons, most are seeing good results - and regardless of WHICH of the L's we're using, Donna/Asher, Libby/Hershey, Denise/Shakes, and I are all posting on the Lantus TR site.
If you're happy with the numbers you're seeing on ProZinc, however, I'd be inclined to seek out more of it. Keep in mind, if you're using small doses, sometimes the vial lasts 6 months, so one vial may be enough to hold you through the shortage.
Hopefully our vets will have something of a stock of Prozinc on hand, so their clients won't be impacted by this. It's good to stay on top of this - so thanks all for posting the links!
Lu-Ann