Lisa, I can't stay to watch you this morning so I'm just going to tell you what I think (remember, I've never used Vetsulin)
Are you going to be home today to test as much as necessary? If so, the 1 unit dose last night actually did OK...he dropped to 76 (which is a safe number), but we don't know what might have happened if you hadn't given the Karo/food....he could have kept dropping or that might have been as low as he was going to go....that's what we mean when we say that Vetsulin usually hits "hard and fast" and then wears off long before the next shot
That being said, I also don't see any reason why you couldn't give .5 this morning if it would make you more comfortable while you're getting used to testing and posting
Might let you "ease into it" a little slower while you're learning