I like raising it every 3rd day, more or less. To me it's less to let their body adjust to it, it's to allow the dose to reach a steady state. With PZI, that is usually accomplished in 2 to 3 cycles as I understand it. Another choice too is to raise in increments of 0.4 rather than 0.2. To me, you can go faster & higher if you aren't seeing good #s. You want to go slower and in smaller increments if the #s are decent, so you don't overdo it. But it doesn't seem like there's much risk of that at the moment.
The nice thing about PZI is that it is so flexible. When cats are doing pretty well symptom-wise and the #s aren't that bad, then it's fine to hold it for several days and move in small increments. If they really aren't acting like they feel well, or the #s just aren't budging much, then I think a more aggressive approach is in order.
In part if we recommend raises less often, it's for practicality - a lot of people don't want to make changes every couple days, it's just too stressful for monitoring and such. Sometimes people want to do something like a curve on a weekend, then raise, and do another curve the next weekend. But IMO in most cases there isn't a specific *need* to wait several days - 5 days, for instance, is an arbitrary amount that allows ample time for the insulin to get to steady-state, some extra time to do some testing, etc. It's more relaxed. But if she isn't feeling well and the #s aren't going anywhere, to me it doesn't make sense to wait that long.
Nothing to be scared of, it's just a process that can be frustrating. I know with Bix I was terrified of both low #s and of high #s, so I feel for you. Once he got to better #s and I could better see how the different doses affected his #s, it got a lot less scary.
Maybe pick somewhere in between 1 day and 5 days and go with that, and/or consider going in increments of 0.4 if you don't want to raise it as often, til you see some better #s. If you are worried about hypos, try to get a test in the 1st half of the cycle to determine whether or not she is going low, and then if you need to you can feed her a little bit to balance the insulin if it turned out to be a little too much. (I don't think you are anywhere close to that, but just mentioning it in case that is one of your worries.)
Sorry if I have scared you too.

Which parts are scaring you? Maybe we can help...?