The best scenerio would be if your vet would realize what a great job you are doing, that you'd have kept him safe when just blindly shooting could have caused a deadly hypo, that U100 syringes will help you give safer doses going forward. I'll keep my fingers crossed that the vet visit will go that way.
It would make no sense to increase the dose, so if the vet says to, I'd just tell him that the nadirs are low enough and he is in regulated numbers and you wouldn't feel safe giving him more insulin. He isn't there when you pull up the insulin, so you can disregard bad advice.
If you can get by with .5, you may be able to lower doses without the U100s but they sure come in handy. If you don't need a prescription in your state, you could always pick up a few (they are not very expensive) Then when .5 works, use the U40s. When .8 is needed, use the U100s. What is the vet's issue? Have you showed him the conversion chart? It's just math, not vodoo. :mrgreen: Diluting the insulin is NOT a good idea.