Just for explanation purposes

my reasoning on pulling back the dose is not so much that it's close to the no shoot, it's because the PS is SOOOOO much lower than this morning's. If you got close to a 50% reduction in the PS on this cycle, you don't really want to continue with that - that would leave tomorrow morning potentially in the low blues, too low to shoot.
You got about a 50% drop today, so in theory on the same dose tonight the nadir might be around 100, not scary at all. But I agree if you can't monitor, and everything is still new and you are in the data gathering phase, I wouldn't put the theory to the test!
What is AWESOME is that he is seeing some really nice PSs as well as a clear response, which are great signs that he will do well on this insulin (YYYAAAAYYYY!!!!) Really you are already to the fine-tuning point, so that is very cool! It's just a matter of figuring out dose will get you some steadiness (hopefully) in the numbers. Ideally you want the PSs to be fairly equal, rather than what he is doing sometimes of sort of alternating between high ones and good ones.
I would probably be trying something like 1u in general, and maybe 1.1 or a fat 1 if he is over 400 to bring the #s back down quickly (seemed to work well today!). Really looking good overall, tho I'm sure the variable numbers are exhausting to try to keep up with and make any sense of!