David, I was going to post that I would not have the pharmacy dilute your insulin, and I doubt that they would even agree to do that. I see that you've already found that out.
It does poses a risk of contamination and infection, and it won't last as long, as the preservatives won't be effective.
The syringes with half unit markings should be sufficient, but there are also pens that do half unit doses. NovoLog can be used in these pens, as they are made by the same company. http://www.novolog.com/
http://www.novolog.com/InsulinDiabetes/OtherDeliverySystems.aspx
I don't think you're going to need to worry about diluting the insulin anyway. If you start treating for your highest carb meal of the day, when your blood sugar is already at its peak, (which sounds like your supper meal), you could try .5 of a unit, (as long as your doctor approves it). Monitor it closely, and see how it goes. I would start with only one dose per day, because that may be all you need for now. I would not do more than one until you know how your body handles it.
Make sure you wait at least 4 days to see how it affects you. It can take that long for the true results to show. I would wait a week before making any increases, as you are eating such a low amount of carbs, and don't have a lot of room for error.
Take it slowly.
The other option would be to take a basal insulin in the morning, which would help keep your blood sugar lower during the day, without as big a risk of lows, as using the mealtime insulins. If the mealtime insulin doesn't work well because of the Dr Bernstien "diet", you could give that option a try later on.