Dana, it's not that you don't want the nadir to be 50% less than pre-shot, it's that when kitty drops that much, it can set off a bounce. Some cats bounce more than others. Hitch is getting a good run of blue numbers mid cycle but it looks like his nadir is early. I'd be interested to see what is happening a little later in the cycle before making any dose change.
Is it possible to get some readings from +6 to +8 or 9 to see how long his surf in the blues is lasting? The goal is to get Hitch into good numbers for as much of each cycle as possible. While it would be nice to get those pre-shot numbers down a bit, it looks to me like he needs more rather than less insulin to do that but that also means his mid cycle numbers will be lower, possibly lower than you are comfortable dealing with at this point. The best thing to do right now is see if he stops bouncing. Bounces can last for 3 days so try to be patient and try to get some readings later in the cycle. If he is maintaining that blue surf later into the cycle it might make you feel a bit better about how Hitch is doing right now.