the ears grow more capillaries as you poke them. it takes about 2 weeks for them to bleed pretty much every poke. until then, just be persistent. your poking helps grow new vessels. but if you or spookie are melting down, give each of you a treat and let it go. try again later. on this site we like to say "it's a marathon, not a sprint."
your vet is old school on the insulin. studies have shown that Lantus and Levemir provide long lasting control and are absolutely the best for cats. PZI is the next on the list. people change insulins without a problem - it shouldn't be a problem for spookie to change. but i understand your concern about the vet - you'll have to figure out what you want to do there. There is an excellent track record of cats who are put on the Rand/Roomp Protocol for dosing going off of insulin fairly quickly. that protocol is for Lantus or Levemir.
most newbies wouldn't want studies thrown at them, but if you're a nurse, perhaps you would. if you want it i'll post it for you.
funny how the universe works to bring us cats that are meant for us, isn't it? i think the same thing about my punkin. he got overlooked at the shelter for about 3 months, and i think he's the best cat ever. the new vet that i'm going to said maybe it was because of his diabetes - i said "but he wasn't diabetic then" and she said "but he would become diabetic." doo dee doo dee - but it's true - punkin is diabetic because of a tumor and probably most people wouldn't have gone to the lengths we've gone to for him. i'm just glad we have him.
so spookie is only 2.5 yrs old . . . has he recently been given steroids of any kind? that can cause diabetes. does he have any other health conditions? asthma?
i'm glad spookie found you. obviously you are just right for him!!!
edited to add: i just decided to get the link for you while i'm thinking of it. here ya go:
Feline Diabetes: Which Insulin do i Choose and How do I adjust the Dose? The study was done by Jacquie Rand and Rhett Marshall, School of Vet Science, University of Queensland, Brisbane, Australia. It was published in 2006 and updated in 2008. i've collected a zillion articles on feline diabetes and related topics. if you want more, just say so.
that link does include a section on dosing with lente or NPH insulins - i *think* humulin is in that category but i'm not certain so you'll want to look into that before using these dosing guidelines.