I agree 1.4 is too much, but I think it may still be useful on a high PS to bring the #s down. I'd probably try a skinny 1.4 though in that case. It's possible that if you stick with 1.3 for a few cycles that may prove to be enough, but the 1.2 and the fat 1.2 haven't looked to me to be enough. The 1.3 wasn't looking to be enough, but sometimes they will do better on cycle 4, so I wouldn't say for sure that 1.3 won't work.
Her #s make a fair amount of sense to me and I feel clear on what I would do in your shoes (of course I might be wrong!), but you need to do what feels right to you. That's what I did with Bix, and although I made a lot of mistakes and put him in high #s a lot more than I probably needed to, it was what I had to do for my own sanity, and thankfully he was pretty forgiving.

That's how you learn, trying things and gathering data, so if your dosing decision doesn't work out one time, you try again next time and do better.
For those reading, I'm not sure Robin means to be using a sliding scale - I've been advising her to experiment with doses in-between 1.2 & 1.4 to try to find the sweet spot. To me, 1.2 looks to be too little & 1.4 too much, but with the trials she did on 1.2F and 1.3, they didn't see to be working well. So that's where the 1.4 came back in, to break back down through the #s, but it still looks to me to be too much for an ongoing dose.
We switched from Vetsulin to PZI, and I struggled for a while too getting used to the differences. I think the biggest things that I had to get used to are to look at PZI in terms of both the current shot and the shot before (a 1.3 following a 1.4 will probably give you better #s than a 1.3 following a 1.2 - I've been calling that overlap, or momentum), and to see that the drops aren't a given.
My experience with Vetsulin was that you could set your clock by the amount of drop you would get off a certain dose. With PZI, it's a toss-up whether you will see that drop, or not much of anything. From what I have seen with PZI, for some cats there is a sweet spot with the dose - a hair too low and it's like shooting water, a hair too high and you're scrambling for the hypo kit (ok, not THAT extreme hopefully!). I found that really frustrating. From what I can tell you can't aim for a "safe" nadir like 100 and have much hope of achieving that. Bix was all 250 nadir, or 50, with little middle ground. I think it has something to do with their body utilizing the insulin well if it's the right dose (maybe with pancreas being able to kick in at the same time to give better #s? not sure about that), but I'm not really sure, it's just what I've seen.
Robin, don't beat yourself up. There is no right answer - PZI is so flexible it's more a variety of approaches, any of which can be successful if they work for a given cat. She has seen some really good #s, so you know she is responding well, it's just a matter of finding the groove.