A suggestion -- you might want to change your subject line to get some former PZI users to stop by. Maybe changing it to PZI vs. Lantus?
A couple of thoughts for your consideration...
I think no matter which insulin you ultimately decide is the right insulin for Tuffy, you need to think about your goals. With the situation of Tuffy living at your office and the limitations regarding monitoring, safety becomes a very real concern. We advocate in favor of a fair amount of testing and from the look of Tuffy's SS, this doesn't seem possible. One thought is to see if there is someone who can take Tuffy home with them evenings and weekends since from what I recall, your dogs would not welcome a cat at your home.
If that's not a reasonable solution, tight regulation or remission may not be feasible given that you would need to run Tuffy's numbers in lower ranges, monitor far more frequently, and use food to bring low numbers up. If your goal is to keep Tuffy's numbers in the 200 range, that may be possible with limited testing. (I say "may" because a lot depends on the cat and they typically do not communicate their intentions terribly well - or not in a language we humans understand!)
I'm not intimately familiar with the use of PZI and I don't want to provide you with misinformation. However, what may be easier and potentially safer for Tuffy, is that dosing is based on pre-shot numbers whereas with Lantus, dosing is based on the nadir. I suspect you still need to get in some mid-cycle tests with PZI, but it may not be quite as essential as it is with Lantus. I do know that ProZinc, the current iteration of PZI, is a longer acting type of insulin but I do not know if the shooting schedule is as inflexible as Lantus.