I would probably go to 1.4 in the morning if the PS isn't under 300. Although it can take a couple days to really see what a dose is doing, since this is a lowered dose, if anything I would expect the results to be lesser on day 2 than on day 1, as you are coming down off more insulin. When you are raising a dose, that's where I've seen increased impact from the dose on cycle 3 or 4, which is where you want to be sure to wait that long so you don't raise the dose on top of it gaining strength on it's own.
Not sure if that made sense :? but basically I'd say if you don't see a better PS or nadir in a cycle or 2, you can safely conclude this dose is too little, and there's no point (especially if you have a ketone history) in waiting longer. You saw a nice U-curve today, though too shallow, so I don't see any signs of wonkiness or anything to consider holding much longer at this dose if tonight doesn't prove any better than today did. Nice not to see any reds though, and yellows are still something to cheer about!!! I'm guessing you may end up needing something like 1.6, but we'll see what happens!!!