Sorry you accepted so quickly; I was just getting started answering your question.
I was going to say that feeding a meal late at night might help with morning vomiting.
Giving a dose of Pepcid AC (famotidine) at 1/4 of a 10 milligram tablet at bedtime might also be helpful.
Vomiting in cats is a big diagnostic challenge. Dozens, even a hundred reasons for cat to vomit. I would try a small late meal, which should not upset the diabetes
, and/or the famotidine. If that does not help, a glucose curve (checking blood glucoses every couple of hours all day ) will tell you for certain if this is due to an improper (too high or too low) insulin dose.
If your cat has not had a pancreas panel (blood tests called PLI and TLI ) done, that would be a good idea. Chronic pancreatitis is common in cats, causes intermittent vomiting, and cannot be diagnosed on routine blood tests.
Sorry I did not get to finish before you accepted, but thank you for the accept.
I will send this as an Info Request, so you do not have to pay again.