I am not saying you shouldn't shoot under 170; I just don't feel comfortable advising people to do that. And what happened with Andyq last night is a pattern that is always a puzzle for me. Logically he should drop - probably a lot after insulin on a low number. But sometimes they rise. (A bean on Vetsulin - which works like PRoZinc - had the same experience last night. That cat jumped right up after a shot on a low pmps. He eventually went down around +8 and then bounced for amps). All I can think is their body panics and releases extra glucose immediately and they jump up right after the shot.
My idea is to stall with a lower preshot than you want to shoot. Wait 20 minutes without feeding and retest. If he is rising and nearer your target number, then shoot. If you have to stall over 40 minutes or so and it is still too low, then you can feed, wait 2 hours and shoot. But yes, it messes up your schedule.
I don't know about R. Some Lantus users use it if they just can't maintain their cat in good ranges. But Andy is looking Good.