Sharon,
Are you going to be home tomorrow? If so, then I think you could give a .5u dose on a number somewhere above 150. Maybe 170? Every cycle is not going to be the same. But today, he started at 196, and dropped down to 92 on that dose. Had that been a 170, he may have dropped down into the 60s.
If you can monitor him, I think 170 might be a good "line in the sand". And, you would want to get a test around +4 to see how low he is. If he is below 100 at that point, then you could give him a small meal to slow the dropping numbers down.
You may see a number higher than recent numbers in the morning, since he will have not had a shot in 24 hours. But after skipping yesterday, he didn't really go "high" by this morning. If you see a number below 150 in the morning, of course skip the shot. But if that happens, it could be time to reduce his dose even lower whenever he does actually need some insulin. We can cross that bridge when we come to it!
I'm not sure if Virginia requires a prescription for syringes. Every state has different laws for that. Your vet would know. He may not even realize that they come with 1/2 unit marks. You might have to call around to different pharmacies to make sure they have them on hand.
Carl