Hi, Eric.
I'm a transplant to Columbus from Chicago. I've been in Ohio for a year now and I miss everything except my job in Chicago!!
How long ago was Wrigley having issues with ketones? (And which vet are you using in Chicago? I was using Cat Hospital and really do recommend them. They saved Gabby's life.)
A few words about ketones...
Ketones develop usually due to an infection or an inflammation being present along with not enough insulin and not enough calories being consumed. Because a cat isn't eating or not eating well, there isn't enough of the usual food to be metabolized so stored fat is being broken down and that's what produces ketones and throws electrolytes out of balance. Looking at Wrigley's SS, if ketones are still present or it's recent enough that it's a concern, Wrigley would be better off with your not reducing the insulin dose unless the numbers indicate you need to and instead, feeding a higher carb food.
Clavamox is an antibiotic so it looks like there was an infection. I'm assuming this is in pill form. (Sometimes the liquid form of medications is in a sugar syrup base -- not a good thing for a diabetic cat!) Obviously, Wrigley's potassium levels were off, as well. This can happen with DKA -- potassium and phosphorus levels are affected. If Wrigley wasn't eating prior to the ketones developing, there may have been some issues with hepatic lipidosis (aka "fatty liver") and the denamarin is good for liver support.
Do you have Ketostix? You can get them at pretty much any pharmacy. You can Wrigley's urine for ketones or an alternative, is to get a meter, either a NovoMax or Precision Xtra, both test blood ketones. The ketone test strips are expensive and unless ketones are repeatedly a problem, testing urinary ketones is what most of us do.